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    <title>Berns, P.M.J.J.</title>
    <link>http://repub.eur.nl/res/aut/4730/</link>
    <description>List of Publications</description>
    <language>en</language>
    <image>
      <url>http://repub.eur.nl/static-eur/img/logo.png</url>
      <title>RePub, Erasmus University Rotterdam</title>
      <link>http://repub.eur.nl</link>
    </image>
    <item>
      <title>Genomic aberrations relate early and advanced stage ovarian cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/38575/</link>
      <pubDate>2012-06-01T00:00:00Z</pubDate>
      <description>Background Because of the distinct clinical presentation of early and advanced stage ovarian cancer, we aim to clarify whether these disease entities are solely separated by time of diagnosis or whether they arise from distinct molecular events. Methods Sixteen early and sixteen advanced stage ovarian carcinomas, matched for histological subtype and differentiation grade, were included. Genomic aberrations were compared for each early and advanced stage ovarian cancer by array comparative genomic hybridization. To study how the aberrations correlate to the clinical characteristics of the tumors we clustered tumors based on the genomic aberrations. Results The genomic aberration patterns in advanced stage cancer equalled those in early stage, but were more frequent in advanced stage (p=0.012). Unsupervised clustering based on genomic aberrations yielded two clusters that significantly discriminated early from advanced stage (p= 0.001), and that did differ significantly in survival (p= 0.002). These clusters however did give a more accurate prognosis than histological subtype or differentiation grade. Conclusion This study indicates that advanced stage ovarian cancer either progresses from early stage or from a common precursor lesion but that they do not arise from distinct carcinogenic molecular events. Furthermore, we show that array comparative genomic hybridization has the potential to identify clinically distinct patients. </description>
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      <title>Microarray-Based oncogenic pathway profiling in advanced serous papillary ovarian carcinoma (Article)</title>
      <link>http://repub.eur.nl/res/pub/34664/</link>
      <pubDate>2011-07-29T00:00:00Z</pubDate>
      <description>Introduction: The identification of specific targets for treatment of ovarian cancer patients remains a challenge. The objective of this study is the analysis of oncogenic pathways in ovarian cancer and their relation with clinical outcome. Methodology: A meta-analysis of 6 gene expression datasets was done for oncogenic pathway activation scores: AKT, β-Catenin, BRCA, E2F1, EGFR, ER, HER2, INFα, INFγ, MYC, p53, p63, PI3K, PR, RAS, SRC, STAT3, TNFα, and TGFβ and VEGF-A. Advanced serous papillary tumours from uniformly treated patients were selected (N = 464) to find differences independent from stage-, histology- and treatment biases. Survival and correlations with documented prognostic signatures (wound healing response signature WHR/genomic grade index GGI/invasiveness gene signature IGS) were analysed. Results: The GGI, WHR, IGS score were unexpectedly increased in chemosensitive versus chemoresistant patients. PR and RAS activation score were associated with survival outcome (p = 0.002;p = 0.004). Increased activations of β-Catenin (p = 0.0009), E2F1 (p = 0.005), PI3K (p = 0.003) and p63 (p = 0.05) were associated with more favourable clinical outcome and were consistently correlated with three prognostic gene signatures. Conclusions: Oncogenic pathway profiling of advanced serous ovarian tumours revealed that increased β-Catenin, E2F1, p63, PI3K, PR and RAS -pathway activation scores were significantly associated with favourable clinical outcome. WHR, GGI and IGS scores were unexpectedly increased in chemosensitive tumours. Earlier studies have shown that WHR, GGI and IGS are strongly associated with proliferation and that high-proliferative ovarian tumours are more chemosensitive. These findings may indicate opposite confounding of prognostic versus predictive factors when studying biomarkers in epithelial ovarian cancer. </description>
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      <title>Correlation of breast cancer susceptibility loci with patient characteristics, metastasis-free survival, and mRNA expression of the nearest genes (Article)</title>
      <link>http://repub.eur.nl/res/pub/24041/</link>
      <pubDate>2011-07-12T00:00:00Z</pubDate>
      <description>To understand the biology of low-risk breast cancer alleles, and to investigate whether these loci also contribute to disease progression that was once established, we examined the association of SNPs tagging the low-risk breast cancer loci in or near FGFR2, LSP1, MAP3K1,H19, TOX3, POU5F1P1, MYC, and 2q35, with clinical, pathological characteristics, prognosis, and mRNA expression of the nearest genes. Tumor DNA samples of 2,480 breast cancer patients were available. Out of this cohort, 1,290 patients with lymph-node negative disease who did not receive adjuvant systemic therapy, the SNP status was associated with metastasis-free survival (MFS). In 1,401 patients, the mRNA expression levels of FGFR2, LSP1, MAP3K1,H19, TOX3, POU5F1P1, and MYC were determined and correlated with SNP genotypes. The SNP rs2981582 in FGFR2 was significantly associated with positive ER and PgR status (P &lt; 0.001 and P = 0.003, respectively). No other significant associations with patient or tumor characteristics were observed. Only rs2107425 near H19 was significantly associated with shorter MFS in uni- and multi-variate analysis (HR: 1.53, CI: 1.12-2.08, P = 0.006 and HR: 1.59, CI: 1.16-2.20, P = 0.004, respectively), with the more aggressive minor allele displaying a recessive trait. The minor allele of SNP rs3803662 located near the TOX3 gene was associated with lower mRNA expression of this gene. In conclusion, except for the association of rs13283662 with TOX3 gene expression indicating a tumor suppressor role of TOX3, our findings suggest that breast cancer low-risk loci generally do not affect expression of the nearest gene in breast tumor tissue. Also the prognosis of patients is largely not affected by low-risk breast cancer loci except for the SNP near H19. How, this SNP affects prognosis warrants further study as it does not operate through altering H19 mRNA expression. </description>
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      <title>Chemosensitivity and outcome of BRCA1- and BRCA2-associated ovarian cancer patients after first-line chemotherapy compared with sporadic ovarian cancer patients (Article)</title>
      <link>http://repub.eur.nl/res/pub/25694/</link>
      <pubDate>2011-06-06T00:00:00Z</pubDate>
      <description>Background: Because it is insufficiently clear whether BRCA-associated epithelial ovarian cancer (EOC) is more chemosensitive than sporadic EOC, we examined response to chemotherapy, progression-free survival (PFS) and overall survival (OS) in BRCA1- and BRCA2-associated versus sporadic EOC patients. Methods: Data about patient characteristics, response to and outcome after primary therapy, including chemotherapy, were collected from 99 BRCA1, 13 BRCA2 and 222 sporadic patients. Analyses were carried out using a chi-square test and Kaplan-Meier and Cox regression methods. Results: Complete response (CR) or no evidence of disease (NED) was observed in 87% of the BRCA1 patients, progressive disease (PD) in 2%, being 71% and 15%, respectively, in sporadic EOC patients (P = 0.002). In BRCA2 patients, 92% had CR/NED, and none PD (P = 0.27). Median PFS in BRCA1, BRCA2 and sporadic patients was 2.1 [95% confidence interval (CI) 1.9-2.5] years (P = 0.006), 5.6 (95% CI 0.0-11.5) years (P = 0.008) and 1.3 (95% CI 1.1- 1.5) years, respectively. Median OS in the three groups was 5.9 (95% CI 4.7-7.0) years (P &lt; 0.001), &gt;10 years (P = 0.008), and 2.9 (95% CI 2.2-3.5) years, respectively. A trend for a longer PFS and OS in BRCA2 compared with BRCA1 patients was observed. Conclusion: Compared with sporadic EOC patients, both BRCA1- and BRCA2-associated patients have improved outcomes after primary therapy, including chemotherapy. </description>
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      <title>CYP2C19*2 polymorphism is associated with increased survival in breast cancer patients using tamoxifen (Article)</title>
      <link>http://repub.eur.nl/res/pub/22062/</link>
      <pubDate>2010-10-01T00:00:00Z</pubDate>
      <description>Abstract

AIMS: Variant alleles of the CYP2C19 gene were recently associated with survival in breast cancer patients on tamoxifen therapy. CYP2C19 is one of the enzymes involved in the metabolism of tamoxifen into active metabolites. We investigated the hypothesis that CYP2C19*2 and *3 variants, known for their lack of enzyme activity, are associated with an increased breast cancer mortality rate in patients using tamoxifen.

MATERIALS &amp; METHODS: In the prospective population based Rotterdam study, the association between CYP2C19*2 carriers and breast cancer mortality was studied among 80 incident users of tamoxifen. Survival was analyzed with life tables and Cox regression analysis, with drug exposure as a time-dependent variable. Adjustments were made for calendar time, average tamoxifen dose, age, the indication for tamoxifen, CYP2D6 genotype and concomitant use of CYP2C19 inhibitors or inducers.

RESULTS: In patients on tamoxifen, CYP2C19*2 carriers were associated with a significantly longer breast cancer survival rate than patients with the wild-type (hazard ratio 0.26, 95%CI: 0.08-0.87).

CONCLUSION: This study suggests that CYP2C19 genotype may possibly be a predictive factor for survival in breast cancer patients using tamoxifen.</description>
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      <title>The impact of CYP2D6-predicted phenotype on tamoxifen treatment outcome in patients with metastatic breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/22063/</link>
      <pubDate>2010-09-07T00:00:00Z</pubDate>
      <description>Abstract

BACKGROUND: Cytochrome P450 2D6 (CYP2D6) has a crucial role in the metabolic conversion of tamoxifen into the active metabolite endoxifen. In this cohort study, the effect of CYP2D6-predicted phenotype, defined as the combined effect of CYP2D6 genetic variation and concomitant use of CYP2D6-inhibiting medication, on time to breast cancer progression (TTP) and overall survival (OS) in women who use tamoxifen for metastatic breast cancer (MBC) was examined.

METHODS: We selected patients treated with tamoxifen (40 mg per day) for hormone receptor-positive MBC from whom a blood sample for pharmacogenetic analysis (CYP2D6*3, *4, *5, *6, *10 and *41) was available. Patient charts (n=102) were reviewed to assess TTP and OS, and to determine whether CYP2D6 inhibitors were prescribed during tamoxifen treatment.

RESULTS: OS was significantly shorter in patients with a poor CYP2D6 metaboliser phenotype, compared with extensive metabolisers (HR=2.09; P=0.034; 95% CI: 1.06-4.12). Co-administration of CYP2D6 inhibitors alone was also associated with a worse OS (HR=3.55; P=0.002; 95% CI: 1.59-7.96) and TTP (HR=2.97; P=0.008; 95% CI: 1.33-6.67) compared with patients without CYP2D6 inhibitors.

CONCLUSION: CYP2D6 phenotype is an important predictor of treatment outcome in women who are receiving tamoxifen for MBC. Co-administration of CYP2D6 inhibitors worsens treatment outcome of tamoxifen and should therefore be handled with care.</description>
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      <title>MicroRNAs in ovarian cancer biology and therapy resistance (Article)</title>
      <link>http://repub.eur.nl/res/pub/22066/</link>
      <pubDate>2010-08-01T00:00:00Z</pubDate>
      <description>Abstract

Epithelial ovarian cancer is the most common cause of death from gynecological malignancies in the Western world. The overall 5-year survival is only 30% due to late diagnosis and development of resistance to chemotherapy. There is, therefore, a strong need for prognostic and predictive markers to help optimize and personalize treatment hence ameliorating the prognosis of ovarian cancer patients. Since 2006, an increasing number of studies have indicated an essential role for microRNAs in ovarian cancer tumorigenesis. In this review, we provide an overview of the microRNAs that have been associated with different aspects of ovarian cancer, such as tumor subtype, stage, histological grade, germline mutations in BRCA genes, prognosis and therapy resistance. We highlight the role of the let-7 and miR-200 families, two major microRNA families that are frequently dysregulated in ovarian cancer and have been associated with poor prognosis. Interestingly, both have been implicated in the regulation of the epithelial-to-mesenchymal transition, a cellular transition associated with tumor aggressiveness, tumor invasion and chemoresistance. Furthermore, we discuss several other microRNAs that have been associated with chemotherapy resistance, such as miR-214, miR-130a, miR-27a and miR-451. In the final section, we speculate on the possibilities of microRNA-based therapies and the use of microRNAs as diagnostic tools.</description>
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      <title>Pathway analysis of gene lists associated with platinum-based chemotherapy resistance in ovarian cancer: the big picture (Article)</title>
      <link>http://repub.eur.nl/res/pub/22065/</link>
      <pubDate>2010-05-01T00:00:00Z</pubDate>
      <description>Abstract

OBJECTIVE: Ovarian cancer is the leading cause of death from gynecological cancers in the Western world (Parkin et al., 2005). The overall 5-year survival is only 30% (Moss and Kaye, 2002), which is for a significant part due to platinum-based chemotherapy resistance. In this study, we performed a pathway analysis on nine published gene sets associated with platinum resistance in ovarian cancer, including a study by us. With this exploratory study, we aim to identify overlapping pathways associated with platinum-based chemotherapy resistance mechanisms in ovarian cancer.

METHODS: Gene Ontology (GO) analysis and Ingenuity Pathway Analysis (IPA) were performed to determine which functional processes were differentially represented in the combined gene lists of nine studies (457 genes) compared to all Unigene identifiers or the Ingenuity knowledge base.

RESULTS: The GO and IPA analysis resulted in the generation of 23 gene networks, and showed that 13 GO processes (&gt;or=2 times enriched), 71 canonical pathways (p&lt;0.05,), eight toxicity pathways (p&lt;0.05) and 74 biological functions (p&lt;0.005) are significantly associated with the 9-study gene set.

CONCLUSION AND RECOMMENDATIONS: Several pathways identified have previously been shown to be associated with therapy resistance: these include 'oxidative stress response mediated by Nrf2,' 'TP53 signaling' and 'TGFbeta signaling.' The role of TGFbeta signaling and related miRNAs identified in the network analysis in epithelial-to-mesenchymal transition (EMT) and stemness as well as the possible relation with platin-based chemotherapy resistance are further discussed in detail. We propose that future international cooperation should aim at a uniform pooled analysis of the wealth of ovarian cancer array data already available. This will enhance the power of each separate ovarian cancer study and can lead to promising results.</description>
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      <title>Differential transport of platinum compounds by the human organic cation transporter hOCT2 (hSLC22A2) (Article)</title>
      <link>http://repub.eur.nl/res/pub/22068/</link>
      <pubDate>2010-02-01T00:00:00Z</pubDate>
      <description>Abstract

BACKGROUND: Solute carriers (SLCs), in particular organic cation transporters (OCTs), have been implicated in the cellular uptake of platinum-containing anticancer compounds. The activity of these carriers may determine the pharmacokinetics and the severity of side effects, including neuro- and nephrotoxicity of platinum-based chemotherapy. As decreased drug accumulation is a key mechanism of platinum resistance, SLCs may also contribute to the development of resistance. Here, we define the role of hSLC22A2 (OCT2) in the cellular uptake of platinum compounds.

EXPERIMENTAL APPROACH: Human embryonic kidney (HEK) 293 cells stably expressing the hSLC22A2 gene (HEK293/hSLC22A2) were used in platinum accumulation studies. Following a 2 h exposure to various platinum compounds (100 microM), intracellular platinum levels were determined by flameless atomic absorption spectrometry.

KEY RESULTS: HEK293/hSLC22A2 cells, compared with HEK293/Neo control cells, displayed significant increases in oxaliplatin (28.6-fold), Pt[DACH]Cl(2) (20.6-fold), ormaplatin (8.1-fold), tetraplatin (4.5-fold), transplatin (3.7-fold) and cisplatin (1.3-fold), but not carboplatin. SLC22A2-mediated transport could be inhibited by 1-methyl-4-phenylpyridinium. Furthermore, hSLC22A2-mediated oxaliplatin and cisplatin accumulation was time- and concentration-dependent, but non-saturable. Expression of hSLC22A2 in HEK293 cells resulted in enhanced sensitivity to oxaliplatin (12-fold) and cisplatin (1.8-fold). Although, hSLC22A2 mRNA expression was frequently found in ovarian cancer cell lines, its expression in clinical ovarian cancer specimens (n= 80) was low and did not correlate with the treatment outcome of platinum-based regimens.

CONCLUSIONS AND IMPLICATIONS: The hSLC22A2 drug transporter is a critical determinant in the uptake and cytotoxicity of various platinum compounds, particularly oxaliplatin.</description>
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      <title>Decreased expression of EZH2 is associated with upregulation of ER and favorable outcome to tamoxifen in advanced breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/22064/</link>
      <pubDate>2010-01-01T00:00:00Z</pubDate>
      <description>Abstract

The purpose of this study is to investigate EZH2 in a large series of breast cancer patients for its prognostic and predictive value, and to evaluate its functional role in treatment response in vitro. EZH2 levels were measured using quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) in primary breast cancer specimens and related to clinicopathologic factors and disease outcome. EZH2 expression was downregulated with siRNAs in MCF7, to assess expression alterations of putative EZH2 downstream genes and to determine cell numbers after treatment with the anti-estrogen ICI 164384. In 688 lymph node-negative patients who did not receive adjuvant systemic therapy, EZH2 was not significantly correlated with metastasis-free survival (MFS). In 278 patients with advanced disease treated with first-line tamoxifen monotherapy, the tertile with highest EZH2 levels was associated with the lowest clinical benefit (OR = 0.48; P = 0.02) and with a shorter progression-free survival (PFS) in both univariate (HR = 1.80; P &lt; 0.001) and multivariate analysis, including traditional factors (HR = 1.61; P = 0.004). In vitro, EZH2 silencing in MCF7 caused a 38% decrease in cell numbers (P &lt; 0.001) whereas ICI 164384 treatment resulted in a 25% decrease (P &lt; 0.001) compared to controls. Combining EZH2 silencing with ICI treatment reduced cell numbers with 67% (P &lt; 0.001) compared to control conditions. EZH2 downregulation was associated with an almost two-fold upregulation of the estrogen receptor alpha (ER) (P = 0.001). In conclusion, EZH2 has no prognostic value in breast cancer. High levels of EZH2 are associated with poor outcome to tamoxifen therapy in advanced breast cancer. Downregulated EZH2 leads to upregulation of the ER and better response to anti-estrogens.</description>
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      <title>Integrated genomics of chemotherapy resistant ovarian cancer: a role for extracellular matrix, TGFbeta and regulating microRNAs (Article)</title>
      <link>http://repub.eur.nl/res/pub/22069/</link>
      <pubDate>2010-01-01T00:00:00Z</pubDate>
      <description>Abstract

Epithelial ovarian cancer is the sixth most common cancer in women worldwide and the most important cause of death from gynaecological cancers in the Western world. Our explorative pathway analysis on seven published gene-sets associated with platinum resistance in ovarian cancer reveals TP53 and transforming growth factor beta as key genes. Furthermore, the extracellular matrix was associated with chemotherapy resistance in ovarian cancer as well as endocrine resistance in breast cancer. Pathway analysis again revealed transforming growth factor beta as a key gene regulating extracellular matrix gene expression. A model is presented based on literature linking transforming growth factor beta, extracellular matrix, integrin signalling, epithelial to mesenchymal transition and regulating microRNAs with a (bivalent) role in chemotherapy response.</description>
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      <title>LH receptor gene expression is essentially absent in breast tumor tissue: Implications for treatment (Article)</title>
      <link>http://repub.eur.nl/res/pub/24466/</link>
      <pubDate>2009-04-10T00:00:00Z</pubDate>
      <description>Worldwide, breast cancer is the most frequently occurring malignancy in women. Early age at full term pregnancy has a protective effect against breast cancer. Evidence coming from a rat breast cancer model suggests a possible role for the pregnancy hormone hCG, a ligand of the LH receptor, as a mediator for this effect. In a previous study, we found that a common polymorphism in the LH receptor associates with tumor progression in premenopausal breast cancer patients, as carriers of the variant receptor showed a shorter disease free survival compared to non-carriers. How hCG and its receptor exert their effects on breast cancer, however, is unclear. One possibility is that these effects take place through LH receptors present in the ovaries, thereby influencing steroid hormone production. Another possibility is that the effects take place through LH receptors present in breast tumor cells themselves, as some studies have detected the receptor in both normal and neoplastic breast tissues and in breast cancer cell lines. To investigate whether a direct effect of LH signaling in breast cancer is likely, we measured LH receptor mRNA expression levels in 1551 breast tumors and 42 different human breast cancer cell lines using a qRT-PCR with a wide dynamic range. In addition, associations between LH receptor expression and clinico-pathologic factors were investigated. Assay validation showed that as little as ∼10 copies per reaction volume of LH receptor cDNA could still be detected by our assay. We show that LH receptors are undetectable in 62% of breast tumor samples and 41 of 42 breast cancer cell lines. For the remaining samples we found expression levels to be very low. Although low, expression of the LH receptor appears to be associated with normal breast cells, favorable tumor characteristics and low tumor percentage. Since expression of the LH receptor in breast cancer cells is very low, it almost excludes the possibility of direct signaling effects. We therefore conclude that signaling effects of the LH receptor on breast cancer most likely take place by an indirect pathway through the ovaries. </description>
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      <title>The VEGF pathway and the AKT/mTOR/p70S6K1 signalling pathway in human epithelial ovarian cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/24590/</link>
      <pubDate>2009-03-24T00:00:00Z</pubDate>
      <description>Vascular endothelial growth factor (VEGF)-A inhibitors exhibit unseen high responses and toxicity in recurrent epithelial ovarian cancer suggesting an important role for the VEGF/VEGFR pathway. We studied the correlation of VEGF signalling and AKT/mTOR signalling. Using a tissue microarray of clinical samples (N=86), tumour cell immunohistochemical staining of AKT/mTOR downstream targets, pS6 and p4E-BP1, together with tumour cell staining of VEGF-A and pVEGFR2 were semi-quantified. A correlation was found between the marker for VEGFR2 activation (pVEGFR2) and a downstream target of AKT/mTOR signalling (pS6) (R=0.29; P=0.002). Additional gene expression analysis in an independent cDNA microarray dataset (N=24) showed a negative correlation (R=-0.73, P&lt;0.0001) between the RPS6 and the VEGFR2 gene, which is consistent as the gene expression and phosphorylation of S6 is inversely regulated. An activated tumour cell VEGFR2/AKT/mTOR pathway was associated with increased incidence of ascites (χ2, P=0.002) and reduced overall survival of cisplatin-taxane-based patients with serous histology (N=32, log-rank test, P=0.04). These data propose that VEGF-A signalling acts on tumour cells as a stimulator of the AKT/mTOR pathway. Although VEGF-A inhibitors are classified as anti-angiogenic drugs, these data suggest that the working mechanism has an important additional modality of targeting the tumour cells directly. </description>
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      <title>Genomic profiling by array comparative genomic hybridization reveals novel DNA copy number changes in breast phyllodes tumours (Article)</title>
      <link>http://repub.eur.nl/res/pub/15334/</link>
      <pubDate>2009-01-15T00:00:00Z</pubDate>
      <description>Breast phyllodes tumour (PT) is a rare fibroepithelial tumour. The genetic alterations contributing to its tumorigenesis are largely unknown. To identify genomic regions involved in pathogenesis and progression of PTs we obtained genome-wide copy number profiles by array comparative genomic hybridization (CGH).

DNA was isolated from fresh-frozen tissue samples. 11 PTs and 3 fibroadenomas, a frequently occurring fibroepithelial breast tumour, were analyzed. Arrays composed of 2464 genomic clones were used, providing a resolution of ~1.4 Mb across the genome. Each clone contains at least one STS for linkage to the human genome sequence.

No copy number changes were detected in fibroadenomas. On the other hand, 10 of 11 PT (91%) showed DNA copy number alterations. The mean number of chromosomal events in PT was 5.5 (range 0–16) per case. A mean of 2.0 gains (range 0–10) and 3.0 losses (range 0–9) was seen per case of PT. Three cases showed amplifications. DNA copy number change was not related to PT grade. We observed recurrent loss on chromosome 1q, 4p, 10, 13q, 15q, 16, 17p, 19 and X. Recurrent copy number gain was seen on 1q, 2p, 3q, 7p, 8q, 16q, 20.

In this study we used array CGH for genomic profiling of fibroepithelial breast tumours. Whereas most PT showed chromosomal instability, fibroadenomas lacked copy number changes. Some copy number aberrations had not previously been associated with PT. Several well-known cancer related genes, such as TP53 and members of the Cadherin, reside within the recurrent regions of copy number alteration. Since copy number change was found in all benign PT, genomic instability may be an early event in PT genesis.</description>
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      <title>Serum proteomic patterns for ovarian cancer monitoring (Article)</title>
      <link>http://repub.eur.nl/res/pub/30177/</link>
      <pubDate>2008-09-01T00:00:00Z</pubDate>
      <description>We set out to discover ovarian cancer biomarkers useful for monitoring progression during and after chemotherapy and possibly for diagnosis. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry was used to create serum protein profiles of ovarian cancer patients before chemotherapy or at progression (n = 51) (trial initiated by the Gynecological Cancer Cooperative Group of the European Organization for Research and Treatment of Cancer trial) that were compared with those of healthy individuals (n = 31). In addition, sera profiles from ovarian cancer patients after chemotherapy (n = 12) were compared with those of ovarian cancer patients at progression (n = 24). One of the discovered biomarkers was identified and subsequently confirmed and validated using enzyme-linked immunosorbent assay (ELISA). Eight primary (sens = 94%, spec = 97%, P &lt; 0.0001) and seven progression tumor biomarkers (sens = 91%, spec = 97%, P &lt; 0.0001) were discovered. In addition, we discovered eight potential progression monitoring biomarkers (sens = 75%, spec = 83%, P = 0.0008) of which one, a biomarker of 11.7 kd, was further identified as serum amyloid A1. Independent validation (ELISA) showed an elevated expression of this protein at relapse in four of the seven ovarian cancer patients tested. Combining the eight newly discovered progression monitoring biomarkers with CA125 resulted in a clear increase of the sensitivity (91-100%). These biomarkers, in combination with for instance CA125, should be validated in large ovarian cancer and control groups. The resulting multimarker assay could be suitable for disease monitoring during and after therapy and might also be useful for ovarian cancer screening. </description>
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      <title>Association of an extracellular matrix gene cluster with breast cancer prognosis and endocrine therapy response (Article)</title>
      <link>http://repub.eur.nl/res/pub/30212/</link>
      <pubDate>2008-09-01T00:00:00Z</pubDate>
      <description>Purpose: We previously discovered an extracellular matrix (ECM) gene cluster associated with resistance to first-line tamoxifen therapy of patients with metastatic breast cancer. In this study, we determined whether the six individual ECM genes [collagen 1A1 (COL1A1), fibronectin 1 (FN1), lysyl oxidase (LOX), secreted protein acidic cysteine-rich (SPARC), tissue inhibitor of metalloproteinase 3 (TIMP3), and tenascin C (TNC)] were associated with treatment response, prognosis, or both. Experimental Design: In 1,286 primary breast tumors, mRNA expression (quantitative realtime PCR) was related to clinicopathologic factors and disease outcome in univariate and multivariate analysis including traditional factors. Results: TIMP3, FN1, LOX, and SPARC expression levels (continuous variables) were significantly associated with distant metastasis-free survival (MFS) in 680 lymph node-negative untreated patients (P &lt; 0.03). Using a calculated linear prognostic score, these patients were evenly divided into five prognostic groups with a significant difference in 10-year MFS of ∼40% between the two extreme prognostic groups. Furthermore, high TNC expression as continuous variable was associated with (a) shorter MFS in 139 estrogen receptor-positive and lymph node-positive patients who received adjuvant tamoxifen therapy (hazard ratio, 1.53; P = 0.001), and (b) no clinical benefit (odds ratio, 0.81; P = 0.035) and shorter progression-free survival (hazard ratio, 1.19; P = 0.002) in 240 patients in whom recurrence was treated with tamoxifen as first-line monotherapy. These results were also significant in multivariate analyses. Conclusion: FN1, LOX, SPARC, and TIMP3 expression levels are associated with the prognosis of patients with breast cancers, whereasTNC is associated with resistance to tamoxifen therapy. Further validation and functional studies are necessary to determine the use of these ECM genes in decisions regarding treatment and whether they can serve as targets for therapy. </description>
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      <title>Polymorphic variations in exon 10 of the luteinizing hormone receptor: Functional consequences and associations with breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/36026/</link>
      <pubDate>2007-09-30T00:00:00Z</pubDate>
      <description>Polymorphic variation of the LHR gene may affect receptor function and accordingly may influence ovarian steroid hormone action, including steroid hormone-dependent clinical outcome. The functional effects of two single nucleotide polymorphisms (SNPs), i.e. LHR 291Asn/Ser (rs12470652) and 312Ser/Asn (rs2293275) in the biologically interesting exon 10 of the LHR gene are described. Furthermore, ethnic diversity in allele frequencies and genotype distributions of both SNPs was determined. In addition associations with breast cancer were studied in 751 breast cancer patients. In vitro transfection studies revealed altered glycosylation status and increased receptor sensitivity for the 291Ser LHR variant. No functional consequences were observed for the 312SerAsn LHR SNP. The LHR 312Asn allele was slightly more often present in two independent breast cancer patient cohorts as compared to controls (OR = 1.15; p = 0.03 and 1.26; p = 0.001, respectively). In conclusion, although functional changes of the LHR 291Ser candidate allele were observed, no associations with breast cancer were found, while the LHR 312Asn allele can be regarded as a weak breast cancer risk allele. </description>
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      <title>GnRH and LHR gene variants predict adverse outcome in premenopausal breast cancer patients (Article)</title>
      <link>http://repub.eur.nl/res/pub/36885/</link>
      <pubDate>2007-08-10T00:00:00Z</pubDate>
      <description>Background: Breast cancer development and progression are dependent on estrogen activity. In premenopausal women, estrogen production is mainly regulated through the hypothalamic-pituitary-gonadal (HPG) axis. Methods: We have investigated the prognostic significance of two variants of genes involved in the HPG-axis, the GnRH (encoding gonadotropin-releasing hormone) 16Trp/Ser genotype and the LHR (encoding the luteinizing hormone receptor) insLQ variant, in retrospectively collected premenopausal breast cancer patients with a long follow-up (median follow-up of 11 years for living patients). Results: Carriership was not related with breast cancer risk (the case control study encompassed 278 premenopausal cases and 1,758 premenopausal controls). A significant adverse relationship of the LHR insLQ and GnRH 16Ser genotype with disease free survival (DFS) was observed in premenopausal (hormone receptor positive) breast cancer patients. In particular, those patients carrying both the GnRH 16Ser and LHR insLQ allele (approximately 25%) showed a significant increased risk of relapse, which was independent of traditional prognostic factors (hazard ratio 2.14; 95% confidence interval 1.32 to 3.45; P = 0.002). Conclusion: We conclude that the LHR insLQ and GnRH 16Ser alleles are independently associated with shorter DFS in premenopausal patients. When validated, these findings may provide a lead in the development of tailored treatment for breast cancer patients carrying both polymorphisms. </description>
    </item> <item>
      <title>Prognostic value of plasminogen activator inhibitor-1 in head and neck squamous cell carcinoma (Article)</title>
      <link>http://repub.eur.nl/res/pub/36671/</link>
      <pubDate>2007-04-01T00:00:00Z</pubDate>
      <description>Background. Tumor cell biological factors, such as urokinase plasminogen activator (uPA) and its inhibitor plasminogen activator inhibitor-1 (PAI-1), cathepsin D, and c-myc play a role in tumor invasion, metastasis, and proliferation. In this study, the prognostic importance of these factors in patients with primary head and neck squamous cell carcinoma (HNSCC) was evaluated and correlated with clinicopathologic variables. Methods. In 46 paired primary tumors and normal tissues, levels of uPA, PAI-1, cathepsin D, and c-myc amplification were determined. The clinical follow-up was over 10 years. Relationships between cell biological factors and patient and tumor characteristics were studied by the Mann-Whitney test. The Cox proportional hazard model was used for univariate and multivariate analysis. Results. In this study, only a high level of PAI-1 was associated with a significantly shorter disease-free survival (p &lt; .01). PAI-1 levels were higher in tumors with perineural invasion (p &lt; .01). Both PAI-1 and uPA levels were higher in patients who smoked (p &lt; .01 and p = .02). In univariate analysis, smoking (p = .04), excessive alcohol intake (p = .02), perineural invasion (p = .001), and vaso-invasion (p = .009) were associated with a shorter disease-free survival. The only factor related to overall survival was perineural invasion (p = .045). The combination of a high PAI-1 level and perineural invasion appeared to be a significant predictor of a shorter disease-free interval (p = .01). Conclusion. PAI-1 may present a novel prognostic factor for patients with HNSCC. Perineural invasion and PAI-1 level combined seemed to be prognostic for disease-free survival. </description>
    </item> <item>
      <title>HOXB13-to-IL17BR expression ratio is related with tumor aggressiveness and response to tamoxifen of recurrent breast cancer: A retrospective study (Article)</title>
      <link>http://repub.eur.nl/res/pub/36221/</link>
      <pubDate>2007-02-20T00:00:00Z</pubDate>
      <description>Purpose: A HOXB13-to-IL17BR expression ratio was previously identified to predict clinical outcome of breast cancer patients treated with adjuvant tamoxifen. However, this ratio may predict a tumor's response to tamoxifen, its intrinsic aggressiveness, or both. Patients and Methods: We have measured the HOXB13 and IL17BR expression levels by real-time polymerase chain reaction in 1,252 primary breast tumor specimens. Expression levels were normalized to housekeeper gene levels and related to clinicopathologic factors for all patients. The primary objective of this study was to determine the relationship of a HOXB13-to-IL17BR ratio with tumor aggressiveness and/or with response to tamoxifen therapy in estrogen receptor (ER) -positive disease. We selected ER-positive tumors, and clinical end points for the HOXB13-to-IL17BR ratio were disease-free survival (DFS) in patients with primary breast cancer (N = 619) and progression-free survival (PFS) in patients with recurrent breast cancer treated with first-line tamoxifen monotherapy (N = 193). The odds ratio (OR) and hazard ratio (HR) and their 95% CI were calculated, and all P values were two-sided. Results: The HOXB13-to-IL17BR ratio was significantly associated with DFS and PFS. In multivariate analysis, HOXB13-to-IL17BR ratio expression levels were associated with a shorter DFS for node-negative patients only. Corrected for traditional predictive factors, the dichotomized HOXB13-to-IL17BR ratio was the strongest predictor in multivariate analysis for a poor response to tamoxifen therapy (OR = 0.16; 95% CI, 0.06 to 0.45; P &lt; .001) and a shorter PFS (HR = 2.97; 95% CI, 1.82 to 4.86; P &lt; .001). Conclusion: High HOXB13-to-IL17BR ratio expression levels associate with both tumor aggressiveness and tamoxifen therapy failure. </description>
    </item> <item>
      <title>LH receptor gene mutations and polymorphisms: An overview (Article)</title>
      <link>http://repub.eur.nl/res/pub/36143/</link>
      <pubDate>2007-01-02T00:00:00Z</pubDate>
      <description></description>
    </item> <item>
      <title>Mismatch repair and treatment resistance in ovarian cancer. (Article)</title>
      <link>http://repub.eur.nl/res/pub/14026/</link>
      <pubDate>2006-07-31T00:00:00Z</pubDate>
      <description>BACKGROUND: The treatment of ovarian cancer is hindered by intrinsic or acquired resistance to platinum-based chemotherapy. The aim of this study is to determine the frequency of mismatch repair (MMR) inactivation in ovarian cancer and its association with resistance to platinum-based chemotherapy. METHODS: We determined, microsatellite instability (MSI) as a marker for MMR inactivation (analysis of BAT25 and BAT26), MLH1 promoter methylation status (methylation specific PCR on bisulfite treated DNA) and mRNA expression of MLH1, MSH2, MSH3, MSH6 and PMS2 (quantitative RT-PCR) in 75 ovarian carcinomas and eight ovarian cancer cell lines RESULTS: MSI was detected in three of the eight cell lines i.e. A2780 (no MLH1 mRNA expression due to promoter methylation), SKOV3 (no MLH1 mRNA expression) and 2774 (no altered expression of MMR genes). Overall, there was no association between cisplatin response and MMR status in these eight cell lines.Seven of the 75 ovarian carcinomas showed MLH1 promoter methylation, however, none of these showed MSI. Forty-six of these patients received platinum-based chemotherapy (11 non-responders, 34 responders, one unknown response). The resistance seen in the eleven non-responders was not related to MSI and therefore also not to MMR inactivation. CONCLUSION: No MMR inactivation was detected in 75 ovarian carcinoma specimens and no association was seen between MMR inactivation and resistance in the ovarian cancer cell lines as well as the ovarian carcinomas. In the discussion, the results were compared to that of twenty similar studies in the literature including in total 1315 ovarian cancer patients. Although no association between response and MMR status was seen in the primary tumor the possible role of MMR inactivation in acquired resistance deserves further investigation.</description>
    </item> <item>
      <title>Combined vascular endothelial growth factor and TP53 status predicts poor response to tamoxifen therapy in estrogen receptor-positive advanced breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/10121/</link>
      <pubDate>2003-01-01T00:00:00Z</pubDate>
      <description>PURPOSE: In recent studies, we showed that TP53 gene mutation or high
      levels of cytosolic vascular endothelial growth factor (VEGF) in estrogen
      receptor (ER)-alpha-positive primary breast tumors predict a poor disease
      outcome for patients treated with first-line tamoxifen for advanced
      disease. Mutant TP53 may up-regulate VEGF, whereas, on the other hand,
      wild-type TP53 may decrease VEGF production. EXPERIMENTAL DESIGN: In the
      present study, we aimed to assess the combined predictive value of TP53
      gene mutation and VEGF status of 160 advanced breast cancer patients with
      ER-positive tumors who were treated with tamoxifen (median follow-up from
      start of tamoxifen treatment, 64 months). To assess TP53 gene mutation
      status, the entire open reading frame was sequenced; for VEGF status, an
      ELISA was used. RESULTS: In univariate analysis, both TP53 gene mutation
      (28% of the tumors) and a VEGF level above the median value were
      significantly associated with a short progression-free survival,
      post-relapse overall survival, and a poor rate of response to tamoxifen.
      In Cox multivariate regression analysis including the traditional
      predictive factors, the addition of TP53 gene mutation and VEGF status,
      alone or in combination, significantly predicted a poor efficacy of
      tamoxifen treatment. When the two factors were combined, a significantly
      decreased odds ratio was seen for the rate of response (odds ratio, 0.27).
      Similarly, an increased hazard ratio (HR) was seen for progression-free
      survival (HR, 2.32) and post-relapse overall survival (HR, 1.68) in the
      group with mutant TP53 and high VEGF compared with the group with both
      risk factors absent. CONCLUSIONS: Combined TP53 gene mutation status and
      high VEGF levels of ER-positive primary breast tumors independently
      predict a poor course of the disease of patients with advanced breast
      cancer treated with tamoxifen. These patients, having unfavorable tumor
      characteristics, might benefit more from other types of (individualized)
      treatment protocols.</description>
    </item> <item>
      <title>Complete sequencing of TP53 predicts poor response to systemic therapy of advanced breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/9358/</link>
      <pubDate>2000-01-01T00:00:00Z</pubDate>
      <description>TP53 has been implicated in regulation of the cell cycle, DNA repair, and
      apoptosis. We studied, in primary breast tumors through direct cDNA
      sequencing of exons 2-11, whether TP53 gene mutations can predict response
      in patients with advanced disease to either first-line tamoxifen therapy
      (202 patients, of whom 55% responded) or up-front (poly)chemotherapy (41
      patients, of whom 46% responded). TP53 mutations were detected in 90 of
      243 (37%) tumors, and one-fourth of these mutations resulted in a
      premature termination of the protein. The mutations were observed in 32%
      (65 of 202) of the primary tumors of tamoxifen-treated patients and in 61%
      (25 of 41) of the primary tumors of the chemotherapy patients. TP53
      mutation was significantly associated with a poor response to tamoxifen
      [31% versus 66%; odds ratio (OR), 0.22; 95% confidence interval (CI),
      0.12-0.42; P &lt; 0.0001]. Patients with TP53 gene mutations in codons that
      directly contact DNA or with mutations in the zinc-binding domain loop L3
      showed the lowest response to tamoxifen (18% and 15% response rates,
      respectively). TP53 mutations were related, although not significantly, to
      a poor response to up-front chemotherapy (36% versus 63%; OR, 0.34; 95%
      CI, 0.09-1.24). In multivariate analysis for response including the
      classical parameters age and menopausal status, disease-free interval,
      dominant site of relapse, and levels of estrogen receptor and progesterone
      receptor, TP53 mutation was a significant predictor of poor response in
      the tamoxifen-treated group (OR, 0.29; 95% CI, 0.13-0.63; P = 0.0014).
      TP53-mutated and estrogen receptor-negative (&lt;10 fmol/mg protein) tumors
      appeared to be the most resistant phenotype. Interestingly, the response
      of patients with TP53 mutations to chemotherapy after tamoxifen was not
      worse than that of patients without these mutations (50% versus 42%; OR,
      1.35, nonsignificant). The median progression-free survival after systemic
      treatment was shorter for patients with a TP53 mutation than for patients
      with wild-type TP53 (6.6 and 0.6 months less for tamoxifen and up-front
      chemotherapy, respectively). In conclusion, TP53 gene mutation of the
      primary tumor is helpful in predicting the response of patients with
      metastatic breast disease to tamoxifen therapy. The type of mutation and
      its biological function should be considered in the analyses of the
      predictive value of TP53.</description>
    </item> <item>
      <title>Histochemical detection of steroid hormone receptors and steroid action in human tumour cell lines  (Doctoral Thesis)</title>
      <link>http://repub.eur.nl/res/pub/38926/</link>
      <pubDate>1986-09-05T00:00:00Z</pubDate>
      <description>Receptor levels as such will probably never give a 100% accurate prediction about the sensitivity of tumours to hormones, due to the limitations of obtaining truely representative samples of tumour tissues as well as the inherent limitations of the receptor being only one of the parameters involved in steroid hormone action. Both mammary and prostate carcinoma are histopathologically heterogeneous tissues and because most biochemical receptor assays are performed on tissue homogenates, it is difficult to predict responses on the basis of a single biopsy. To allow for a more precise, cell by cell analysis of the receptor content in a heterogeneous tumour specimen, histochemical methods have been developed. With such histochemical methods it might be possible to determine which or how many cells actually contain receptors and these methods might offer also a possibility for detection of receptors in small amounts of tissue or needle aspirations. One of the aims of the studies presented in this thesis was to investigate whether histochemical methods (cytofluorescence, autoradiography and immunocytochemistry) can be used for a reliable determination of steroid hormone receptors (Chapters 4, 5 and 6). It is well known that the binding of the hormone to the receptor is only the first step in a complex pathtvay leading to the physiological effects of hormones. Hence to obtain a proper parameter for hormone actions it would be more meaningful to develop assays that directly measure the responsiveness of tumours with respect to grmowth rather than simply the presence of receptors. In this regard the second aim of our studies was to investigate the effects of steroids on the proliferation of tumour cells in vitro, since steroids may influence cell proliferation and specific protein secretion (Chapter 7).</description>
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