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    <title>Meijer van Gelder, M.E.</title>
    <link>http://repub.eur.nl/res/aut/663/</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>The CYP2C19*2 genotype predicts tamoxifen treatment outcome in advanced breast cancer patients (Article)</title>
      <link>http://repub.eur.nl/res/pub/34368/</link>
      <pubDate>2011-08-01T00:00:00Z</pubDate>
      <description>Aims: Tamoxifen is metabolized by cytochrome P450s, with an important role for CYP2D6. Recently, we demonstrated in 80 patients that CYP2C19*2 is associated with increased survival in breast cancer patients using tamoxifen. Here, we aimed to confirm this in a large group of 499 patients. Materials &amp; methods: A total of 499 estrogen receptor-positive primary breast tumor specimens of advanced disease patients treated with first-line tamoxifen were genotyped for CYP2C19*2 and 17 variant alleles, with primary end point time-to-treatment failure (TTF). Effects of CYP2C19, independent of treatment, were analyzed in 243 primary systematic untreated patients. Results: CYP2C19*2 hetero-and homozygote patients combined showed significantly longer TTFs (hazard ratio [HR]: 0.72; 95% CI: 0.57-0.90; p = 0.004). In multivariate analysis, including CYP2D6*4 status, CYP2C19*2 remained independently associated with TTF (HR: 0.73; 95% CI: 0.58-0.91; p = 0.007). In untreated patients, the CYP2C19*17 allele was significantly associated with a longer disease-free interval (HR: 0.66; 95%CI: 0.46-0.95; p = 0.025). Conclusion: CYP2C19 genotyping is potentially important for tamoxifen therapy for advanced disease and for breast cancer prognosis. </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>CITED2 and NCOR2 in anti-oestrogen resistance and progression of breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/24594/</link>
      <pubDate>2009-12-01T00:00:00Z</pubDate>
      <description>Background:Endocrine therapies of breast cancer are effective but ultimately fail because of the development of treatment resistance. We have previously revealed several genes leading to tamoxifen resistance in vitro by retroviral insertion mutagenesis. To understand the manner in which these genes yield tamoxifen resistance, their effects on global gene expression were studied and those genes resulting in a distinct gene expression profile were further investigated for their clinical relevance.Methods:Gene expression profiles of 69 human breast cancer cell lines that were made tamoxifen resistant through retroviral insertion mutagenesis were obtained using oligonucleotide arrays and analysed with bioinformatic tools. mRNA levels of NCOR2 and CITED2 in oestrogen receptor-positive breast tumours were determined by quantitative RT-PCR. mRNA levels were evaluated for association with metastasis-free survival (MFS) in 620 patients with lymph node-negative primary breast cancer who did not receive systemic adjuvant therapy, and with clinical benefit in 296 patients receiving tamoxifen therapy for recurrent breast cancer.Results:mRNA expression profiles of most tamoxifen-resistant cell lines were strikingly similar, except for the subgroups of cell lines in which NCOR2 or CITED2 were targeted by the retrovirus. Both NCOR2 and CITED2 mRNA levels were associated with MFS, that is, tumour aggressiveness, independently of traditional prognostic factors. In addition, high CITED2 mRNA levels were predictive for a clinical benefit from first-line tamoxifen treatment in patients with advanced disease.Conclusions: Most retrovirally targeted genes yielding tamoxifen resistance in our cell lines do not impose a distinctive expression profile, suggesting that their causative role in cell growth may be accomplished by post-transcriptional processes. The associations of NCOR2 and CITED2 with outcome in oestrogen receptor-positive breast cancer patients underscore the clinical relevance of functional genetic screens to better understand disease progression, which may ultimately lead to the development of improved treatment options. </description>
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      <title>Identification of a putative protein-profile associating with tamoxifen therapy-resistance in breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/22152/</link>
      <pubDate>2009-06-08T00:00:00Z</pubDate>
      <description>Tamoxifen-resistance is a major cause of death in patients with recurrent breast cancer. Current clinical parameters can correctly predict therapy response in only half of the treated patients. Identification of proteins that associate with tamoxifen-resistance is a first step towards better response prediction and tailored treatment of patients. 
In the present study we aimed to identify putative protein biomarkers indicative of tamoxifen therapy-resistance in breast cancer, using nanoLC-FTICR MS. Comparative proteome analysis was performed on ~5,500 pooled tumor cells obtained through laser capture microdissection from two independently processed data sets (n=24 and n=27) of tamoxifen therapy-sensitive and -resistant tumors. Peptide and protein identifications were acquired by matching mass and elution time features to information in previously generated accurate mass and time tag reference data bases.  
A total of 17,263 unique peptides were identified that corresponded to 2,556 non-redundant proteins identified with &gt;=2 peptides. From this total, 1,713 proteins overlapped between the two data sets, which were used for further statistical analysis. Comparative proteome analysis of the two data sets combined revealed 100 putatively differentially abundant proteins (p&lt;0.05) between tamoxifen-sensitive and -resistant tumors. The presence and abundance of 47 of these proteins was verified by targeted nanoLC-MS/MS in the same, individual, non-microdissected tumor tissue extracts. ENPP1, EIF3E, and GNB4 significantly associated with progression-free survival upon tamoxifen treatment (p=0.005, p=0.03 and p= 0.04, respectively).
Differential abundance of our top discriminating protein, EMMPRIN, was validated by tissue microarray in an independent patient cohort (n=156). EMMPRIN was not only higher expressed in PD tumors, it also significantly associated with shorter time to progression upon tamoxifen treatment (p=0.002).
In summary, quantitative comparative proteomics was performed on LCM-derived breast tumor cells using ultra-sensitive nanoLC-FTICR technology; this resulted in the identification of putative biomarkers associating with tamoxifen therapy-resistance in recurrent breast cancer.</description>
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      <title>Urokinase receptor splice variant uPAR-del4/5-associated gene expression in breast cancer: Identification of rab31 as an independent prognostic factor (Article)</title>
      <link>http://repub.eur.nl/res/pub/29309/</link>
      <pubDate>2008-09-01T00:00:00Z</pubDate>
      <description>Purpose: To evaluate the pure prognostic impact of the uPA-receptor splice variant uPAR-del4/5 for lymph node-negative breast cancer patients, and to identify differentially expressed genes associated with high or low uPAR-del4/5 mRNA levels. Patients and methods: mRNA transcript levels were measured by real-time PCR in tumor samples from 280 node-negative breast cancer patients who had not received adjuvant systemic therapy. Endpoints were distant metastasis-free survival (DMFS) and overall survival (OS). Gene expression analysis was performed with RNA isolated from breast cancer tissue and breast cancer cell lines using Affymetrix U133a GeneChips. Results: In multivariate analysis, uPAR-del4/5 significantly contributed to the base model of traditional prognostic factors for DMFS (HR = 3.29, P &lt; 0.001) and OS (HR = 2.87, P = 0.002). Using microarrays, seven genes were found to be up-regulated in tumor samples and cancer cell lines with high uPAR-del4/5 mRNA expression. The gene encoding rab31, a member of the Ras oncogene family, was selected for quantitative analysis of mRNA expression in the set of 280 patients. High rab31 values were significantly associated with worse outcome of patients for DMFS (HR = 2.27, P &lt; 0.001) and OS (HR = 2.01, P = 0.008) in multivariate analysis, independent from uPAR-del4/5. The patient subgroup with high uPAR-del4/5 and rab31 levels showed the worst DMFS and OS (P &lt; 0.001, both) compared with tumors with low values of both factors. Conclusions: Our results suggest that uPAR-del4/5 and rab31 mRNA represent independent prognostic markers in breast cancer and may be components of different, but possibly associated, tumor-relevant signaling pathways. </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>CHEK2 1100delC and male breast cancer in the Netherlands (Article)</title>
      <link>http://repub.eur.nl/res/pub/15959/</link>
      <pubDate>2008-01-01T00:00:00Z</pubDate>
      <description>Mutations in the breast cancer susceptibility genes BRCA1, BRCA2, and CHEK2 are known risk factors for female breast cancer. Mutations in BRCA1 and BRCA2 also are associated with male breast cancer (MBC). Similarly, it had been suggested in the original CHEK2 identification report that the CHEK2 1100delC mutation confers an increased risk for MBC. Here, we have evaluated the risk of CHEK2 1100delC for MBC by genotyping CHEK2 1100delC in 23 familial and 71 unselected Dutch MBC cases. None of the 23 familial MBC cases carried the CHEK2 1100delC mutation. In contrast, CHEK2 1100delC was present in 3 of the 71 (4.2%) unselected MBC cases, which was significantly more prevalent than the 1.1% Dutch population frequency assessed in 1,692 individuals (P = 0.05, OR = 4.1, 95% CI 1.2-14.3). Our data suggest that, in the Netherlands, CHEK2 1100delC is associated with an increased risk for MBC.</description>
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      <title>Concentrations of TIMP1 mRNA splice variants and TIMP-1 protein are differentially associated with prognosis in primary breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/35334/</link>
      <pubDate>2007-07-01T00:00:00Z</pubDate>
      <description>Background: TIMP-1 protein is a prognostic factor for recurrence-free and overall survival (OS) time in breast cancer. We evaluated the prognostic value of TIMP1 mRNA and a novel TIMP1 mRNA splice variant in 1301 primary breast cancer patients. Methods: We measured mRNA transcripts of full-length TIMP1 (TIMPl-v1) and the novel splice variant lacking exon 2 (TIMP1-v2) by use of real-time RT-PCR in frozen primary tumor samples. Transcript concentrations are correlated with histomorphological and biological factors, TIMP-1 protein, and distant metastasis-free survival (MFS) and OS time. Results: TIMP1-v1 and TIMP1-v2 alone were not informative with respect to predicting prognosis. However, the PCR assay designed to measure the combination of v1 + v2 showed that high concentrations of this combination were associated with good prognosis. In Cox multivariate regression analysis, which also included the traditional prognostic factors, increasing concentrations were independently associated with prolonged MFS (P = 0.004) and OS (P = 0.048). Including TIMP-1 protein and TIMP1-v1+v2 mRNA together in the multivariate model revealed that protein and mRNA were both independently associated with prognosis, with hazard ratios pointing in opposite directions. Conclusion: High concentrations of TIMP1-v1+2 mRNA are associated with good prognosis in patients with primary breast cancer. Since high concentrations of TIMP-1 protein are associated with poor prognosis, the presence of possible posttranscriptional mechanisms requires further investigation. </description>
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      <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>
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      <title>How ADAM-9 and ADAM-11 differentially from estrogen receptor predict response to tamoxifen treatment in patients with recurrent breast cancer: a retrospective study. (Article)</title>
      <link>http://repub.eur.nl/res/pub/13955/</link>
      <pubDate>2005-10-15T00:00:00Z</pubDate>
      <description>PURPOSE: To evaluate the predictive value of the disintegrin and metalloproteinases, ADAM-9, ADAM-10, ADAM-11, and ADAM-12, and of the matrix metalloproteinases, MMP-2 and MMP-9, in patients with recurrent breast cancer treated with tamoxifen. EXPERIMENTAL DESIGN: A retrospective study was done on 259 frozen specimens of estrogen receptor-positive primary breast carcinomas from patients who developed recurrent disease and were treated with tamoxifen as the first line of therapy. The expression levels of the biological factors were assessed by real-time quantitative reverse transcriptase PCR. RESULTS: Using log-transformed continuous variables, increasing levels of ADAM-9 [odds ratio (OR) = 1.41; P = 0.015] and decreasing levels of MMP-9 (OR, 0.81; P = 0.035) predicted favorable disease control independent from the traditional predictive factors. Furthermore, when tumors were dichotomized at the median level of 70% tumor cell nuclei, our univariate analysis showed particularly strong results for the group of 153 patients with primary tumors containing 30% or more stromal cells. Although estrogen receptor levels lost their predictive power for this group of patients, high levels of ADAM-9 (OR, 1.59; P = 0.007) and ADAM-11 (OR, 1.65; P = 0.001) were significantly associated with a higher efficacy of tamoxifen therapy. CONCLUSIONS: Our results show that especially for primary tumors containing stromal elements, the assessment of mRNA expression levels of ADAM-9 and ADAM-11 could be useful to identify patients with recurrent breast cancer who are likely to benefit or fail from tamoxifen therapy.</description>
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      <title>Association of DNA methylation of phosphoserine aminotransferase with response to endocrine therapy in patients with recurrent breast cancer. (Article)</title>
      <link>http://repub.eur.nl/res/pub/13806/</link>
      <pubDate>2005-05-15T00:00:00Z</pubDate>
      <description>To understand the biological basis of resistance to endocrine therapy is of utmost importance in patients with steroid hormone receptor-positive breast cancer. Not only will this allow us prediction of therapy success, it may also lead to novel therapies for patients resistant to current endocrine therapy. DNA methylation in the promoter regions of genes is a prominent epigenetic gene silencing mechanism that contributes to breast cancer biology. In the current study, we investigated whether promoter DNA methylation could be associated with resistance to endocrine therapy in patients with recurrent breast cancer. Using a microarray-based technology, the promoter DNA methylation status of 117 candidate genes was studied in a cohort of 200 steroid hormone receptor-positive tumors of patients who received the antiestrogen tamoxifen as first-line treatment for recurrent breast cancer. Of the genes analyzed, the promoter DNA methylation status of 10 genes was significantly associated with clinical outcome of tamoxifen therapy. The association of the promoter hypermethylation of the strongest marker, phosphoserine aminotransferase (PSAT1) with favorable clinical outcome was confirmed by an independent quantitative DNA methylation detection method. Furthermore, the extent of DNA methylation of PSAT1 was inversely associated with its expression at the mRNA level. Finally, also at the mRNA level, PSAT1 was a predictor of tamoxifen therapy response. Concluding, our work indicates that promoter hypermethylation and mRNA expression of PSAT1 are indicators of response to tamoxifen-based endocrine therapy in steroid hormone receptor-positive patients with recurrent breast cancer.</description>
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      <title>The prognostic value of BCAR1 in patients with primary breast cancer. (Article)</title>
      <link>http://repub.eur.nl/res/pub/13506/</link>
      <pubDate>2004-09-15T00:00:00Z</pubDate>
      <description>PURPOSE: BCAR1, the human homologue of the rat p130Cas protein, was
      identified in a functional screen for human breast cancer cell
      proliferation resistant to antiestrogen drugs. Here, we study the
      prognostic value of quantitative BCAR1 levels in a large series of breast
      cancer specimens. EXPERIMENTAL DESIGN: A specific ELISA was developed to
      measure BCAR1 protein levels in 2593 primary breast tumor cytosols. Tumor
      levels of BCAR1 were correlated with relapse-free survival (RFS) and
      overall survival (OS) and compared with collected data on urokinase-type
      plasminogen activator (uPA) and plasminogen activator inhibitor 1 (PAI-1).
      RESULTS: In tumor cytosols, BCAR1 protein levels varied between 0.02 and
      23 ng/mg protein. BCAR1 levels exhibited a positive correlation with
      steroid hormone receptor levels, age and menopausal status, and uPA and
      PAI-1 levels. The level of BCAR1 (continuous or categorized as low,
      intermediate, or high) was inversely related with RFS and OS time.
      Multivariate analysis showed that BCAR1 levels contributed independently
      to a base model containing the traditional prognostic factors for both RFS
      and OS (both P &lt; 0.0001). When added together with uPA and PAI-1 in the
      multivariate model, BCAR1 contributed independently of PAI-1 and was
      favored over uPA. Interaction tests allowed for additional analyses of
      BCAR1 protein levels in clinically relevant subgroups stratified by nodal
      and menopausal status. CONCLUSIONS: The quantitative BCAR1 protein level
      represents a prognostic factor for RFS and OS in primary breast cancer,
      independent of the traditional prognostic factors and the other novel
      marker PAI-1.</description>
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      <title>Urokinase-type plasminogen activator system in breast cancer: association with tamoxifen therapy in recurrent disease. (Article)</title>
      <link>http://repub.eur.nl/res/pub/13436/</link>
      <pubDate>2004-07-01T00:00:00Z</pubDate>
      <description>The prognostic value of components of the urokinase-type plasminogen
      activator (uPA) system, its receptor uPAR (CD87), and plasminogen
      activator inhibitors PAI-1 and PAI-2 is well established. We studied the
      predictive value of these proteolytic factors by evaluating the
      association of their tumor expression level and the efficacy of tamoxifen
      therapy in patients with recurrent breast cancer. The antigen levels of
      the four factors were determined by ELISA in cytosols prepared from
      estrogen receptor-positive primary breast tumors of 691 hormone-naive
      breast cancer patients with recurrent disease and treated with tamoxifen
      as first-line systemic therapy. High tumor levels of uPA (P &lt; 0.001), uPAR
      (P &lt; 0.01), and PAI-1 (P = 0.01) were associated with a lower efficacy of
      tamoxifen therapy. In the multivariable analysis, uPA (P &lt; 0.001) provided
      additional information independent of the traditional predictive factors
      to predict benefit from tamoxifen therapy. High levels of uPA, uPAR, and
      PAI-1 predicted a shorter progression-free survival (PFS) on tamoxifen in
      an analysis of the first 9 months of therapy. However in the analysis
      during the total follow-up period, high PAI-2 levels (P = 0.01) showed a
      longer response to tamoxifen. In conclusion, uPA, uPAR, and PAI-1,
      components of the urokinase system, are predictive for the efficacy of
      tamoxifen therapy in patients treated for recurrent breast cancer.
      Knowledge of their tumor expression levels might be helpful for future
      individualized therapy protocols, including possible new-targeted
      therapies based on the interference in the urokinase system.</description>
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      <title>RNA expression of breast cancer resistance protein, lung resistance-related protein, multidrug resistance-associated proteins 1 and 2, and multidrug resistance gene 1 in breast cancer: correlation with chemotherapeutic response (Article)</title>
      <link>http://repub.eur.nl/res/pub/10101/</link>
      <pubDate>2003-01-01T00:00:00Z</pubDate>
      <description>PURPOSE: The aim of this study was to investigate whether expression of
      particular drug resistance genes in primary operable breast cancer
      correlates with response to first-line chemotherapy in advanced disease.
      EXPERIMENTAL DESIGN: We determined mRNA levels of BCRP, LRP, MRP1, MRP2,
      and MDR1 in 59 primary breast tumor specimens of patients who received
      chemotherapy as first-line systemic treatment after diagnosis of advanced
      disease. The relative expression levels were measured by quantitative
      real-time reverse transcription-PCR and subsequently analyzed in relation
      to the type of response to chemotherapy, the length of progression-free
      survival (PFS), and post-relapse overall survival. RESULTS: For each of
      these drug resistance genes, a large variation in expression level was
      observed among the tumors of the different patients. When analyzing mRNA
      expression in relation to overall response, it was found that the median
      expression level of these five drug resistance genes in the responding
      tumors, as compared with nonresponding tumors, was markedly lower.
      Classification of tumors as high versus low with respect to the expression
      level of these genes showed that the overall response in the MDR1-high
      subset (17%), as compared with the MDR1-low subset (68%), was
      significantly lower (P = 0.005). Although similar differences in response
      rate were found for subsets of tumors stratified by the expression level
      of the other drug resistance genes, none of the observed differences were
      statistically significant. However, in the subgroup of patients treated
      with anthracycline-based chemotherapy (5-fluorouracil,
      Adriamycin/epirubicin, and cyclophosphamide), a correlation between
      response and the expression of BCRP and MRP1 (only PFS) was found, whereas
      such an association was not present in the cyclophosphamide, methotrexate,
      and 5-fluorouracil-treated group of patients. Furthermore, high expression
      of LRP as well as MDR1 was found to be significantly associated with a
      poor PFS (P = 0.04 and P &lt; 0.001, respectively). For lung
      resistance-related protein, this association was limited to
      5-fluorouracil, Adriamycin/epirubicin, and cyclophosphamide. Expression
      levels of BCRP, MRP1, or MRP2 were not related with the length of PFS.
      Furthermore, no correlation between the expression level of these drug
      resistance genes and post-relapse overall survival was found. CONCLUSIONS:
      In this pilot study, MDR1 expression in primary breast tumors was
      inversely related with the efficacy of first-line chemotherapy, and high
      expression level was a significant predictor of poor prognosis for
      patients with advanced disease. Apart from MDR1, the expression levels of
      BCRP, LRP, and MRP1 might have some additional predictive value for
      clinical outcome.</description>
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      <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>
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      <title>Pooled analysis of prognostic impact of urokinase-type plasminogen activator and its inhibitor PAI-1 in 8377 breast cancer patients (Article)</title>
      <link>http://repub.eur.nl/res/pub/9823/</link>
      <pubDate>2002-01-16T00:00:00Z</pubDate>
      <description>BACKGROUND: Urokinase-type plasminogen activator (uPA) and its inhibitor
      (PAI-1) play essential roles in tumor invasion and metastasis. High levels
      of both uPA and PAI-1 are associated with poor prognosis in breast cancer
      patients. To confirm the prognostic value of uPA and PAI-1 in primary
      breast cancer, we reanalyzed individual patient data provided by members
      of the European Organization for Research and Treatment of Cancer-Receptor
      and Biomarker Group (EORTC-RBG). METHODS: The study included 18 datasets
      involving 8377 breast cancer patients. During follow-up (median 79
      months), 35% of the patients relapsed and 27% died. Levels of uPA and
      PAI-1 in tumor tissue extracts were determined by different immunoassays;
      values were ranked within each dataset and divided by the number of
      patients in that dataset to produce fractional ranks that could be
      compared directly across datasets. Associations of ranks of uPA and PAI-1
      levels with relapse-free survival (RFS) and overall survival (OS) were
      analyzed by Cox multivariable regression analysis stratified by dataset,
      including the following traditional prognostic variables: age, menopausal
      status, lymph node status, tumor size, histologic grade, and steroid
      hormone-receptor status. All P values were two-sided. RESULTS: Apart from
      lymph node status, high levels of uPA and PAI-1 were the strongest
      predictors of both poor RFS and poor OS in the analyses of all patients.
      Moreover, in both lymph node-positive and lymph node-negative patients,
      higher uPA and PAI-1 values were independently associated with poor RFS
      and poor OS. For (untreated) lymph node-negative patients in particular,
      uPA and PAI-1 included together showed strong prognostic ability (all
      P&lt;.001). CONCLUSIONS: This pooled analysis of the EORTC-RBG datasets
      confirmed the strong and independent prognostic value of uPA and PAI-1 in
      primary breast cancer. For patients with lymph node-negative breast
      cancer, uPA and PAI-1 measurements in primary tumors may be especially
      useful for designing individualized treatment strategies.</description>
    </item> <item>
      <title>High tumor levels of vascular endothelial growth factor predict poor response to systemic therapy in advanced breast cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/9684/</link>
      <pubDate>2001-01-01T00:00:00Z</pubDate>
      <description>Vascular endothelial growth factor (VEGF), a potent angiogenic factor, has
          been reported to be associated with a poor prognosis in primary breast
          cancer and in several other cancer types. In the present study, we have
          measured with ELISA the levels of VEGF in cytosolic extracts of 845
          primary breast tumors of patients who developed a recurrence during
          follow-up. All of the patients received tamoxifen (n = 618) or
          cyclophosphamide, methotrexate, 5-fluorouracil (CMF) or 5-fluorouracil,
          Adriamycin, cyclophosphamide (FAC) chemotherapy (n = 227) as first-line
          systemic therapy after diagnosis of advanced disease. VEGF levels were not
          related to age or menopausal status but were negatively related to the
          cytosolic levels of estrogen receptor and progesterone receptor (P &lt;
          0.0001). In patients who relapsed within 1 year after primary surgery,
          tumor VEGF levels were higher than in patients who showed a longer
          disease-free interval (P = 0.0005). In patients with a first relapse in
          the viscera, VEGF levels were higher compared with those that relapsed to
          the bone or soft tissue (P = 0.0004). In univariate analysis for response
          to first-line tamoxifen therapy, patients with high or intermediate levels
          showed a poor rate of response, compared with patients with low tumor-VEGF
          levels (P = 0.0001). Similarly, in multivariate analysis for response to
          tamoxifen treatment, corrected for age, site of relapse, disease-free
          interval, and estrogen receptor and progesterone receptor status, VEGF
          status was an independent predictive factor (P = 0.009). In concordance,
          higher levels of VEGF were associated with a short progression-free
          survival and postrelapse overall survival (both, P &lt; 0.0001). On
          first-line chemotherapy, the rate of response decreased with higher tumor
          levels of VEGF, both in univariate (P = 0.003) and in multivariate
          analysis (P = 0.004). Furthermore, higher VEGF levels were associated with
          a short progression-free survival (P = 0.003) and postrelapse overall
          survival (P = 0.001). In conclusion, the tumor VEGF level is an important
          independent marker that predicts a poor efficacy of both tamoxifen and
          chemotherapy in advanced breast cancer. Knowledge of the tumor level of
          VEGF might be helpful in selecting individual patients who may benefit
          from treatments with antiangiogenic agents combined with conventionally
          used drugs.</description>
    </item> <item>
      <title>Bcar1/p130Cas protein and primary breast cancer: prognosis and response to tamoxifen treatment (Article)</title>
      <link>http://repub.eur.nl/res/pub/9229/</link>
      <pubDate>2000-01-01T00:00:00Z</pubDate>
      <description>BACKGROUND: The product of the Bcar1/p130Cas (breast cancer
      resistance/p130Crk-associated substrate) gene causes resistance to
      antiestrogen drugs in human breast cancer cells in vitro. To investigate
      its role in clinical breast cancer, we determined the levels of
      Bcar1/p130Cas protein in a large series of primary breast carcinomas.
      METHODS: We measured Bcar1/p130Cas protein in cytosol extracts from 937
      primary breast carcinomas by western blot analysis. The levels of
      Bcar1/p130Cas protein were tested for associations and trends against
      clinicopathologic and patient characteristics, the lengths of relapse-free
      survival and overall survival (n = 775), and the efficacy of first-line
      treatment with tamoxifen for recurrent or metastatic disease (n = 268).
      RESULTS: Bcar1/p130Cas levels in primary tumors were associated with
      age/menopausal status and the levels of estrogen receptor and progesterone
      receptor. In univariate survival analysis, higher Bcar1/p130Cas levels
      were associated with poor relapse-free survival and overall survival (both
      two-sided P =.04; log-rank test for trend). In multivariate analysis, a
      high level of Bcar1/p130Cas was independently associated with poor
      relapse-free survival and overall survival. The response to tamoxifen
      therapy in patients with recurrent disease was reduced in patients with
      primary tumors that expressed high levels of Bcar1/p130Cas. In
      multivariate analysis for response, Bcar1/p130Cas was independent of
      classical predictive factors, such as estrogen receptor status,
      age/menopausal status, disease-free interval, and dominant site of
      relapse. CONCLUSION: Patients with primary breast tumors expressing a high
      level of Bcar1/p130Cas protein appear to experience more rapid disease
      recurrence and have a greater risk of (intrinsic) resistance to tamoxifen
      therapy. Thus, measurement of Bcar1/p130Cas may provide useful prognostic
      information for patients with primary or metastatic breast cancer.</description>
    </item> <item>
      <title>The urokinase system of plasminogen activation and prognosis in 2780 breast cancer patients (Article)</title>
      <link>http://repub.eur.nl/res/pub/9256/</link>
      <pubDate>2000-01-01T00:00:00Z</pubDate>
      <description>The antigen levels of components of the urokinase-type plasminogen
          activator (uPA) system of plasminogen activation are correlated with
          prognosis in several types of cancers, including breast cancer. In the
          present study involving 2780 patients with primary invasive breast cancer,
          we have evaluated the prognostic importance of the four major components
          of the uPA system [uPA, the receptor uPAR (CD87), and the inhibitors PAI-1
          and PAI-2]. The antigen levels were determined by ELISA in cytosols
          prepared from primary breast tumors. The levels of the four factors
          significantly correlated with each other; the Spearman rank correlation
          coefficients (r(s)) ranged from 0.32 (between PAI-2 and PAI-1 or uPAR) to
          0.59 (between uPA and PAI-1). The median duration of follow-up of patients
          still alive was 88 months. In the multivariate analyses for relapse-free
          survival (RFS) and overall survival (OS), we defined a basic model
          including age, menopausal status, tumor size and grade, lymph node status,
          adjuvant therapy, and steroid hormone receptor status. uPA, uPAR, PAI-1,
          and PAI-2 were considered as categorical variables, each with two cut
          points that were established by isotonic regression analysis. Compared
          with tumors with low levels, those with intermediate and high levels
          showed a relative hazard rate (RHR) and 95% confidence interval (95% CI)
          of 1.22 (1.02-1.45) and 1.69 (1.39-2.05) for uPA, and 1.32 (1.14-1.54) and
          2.17 (1.74-2.70) for PAI-1, respectively, in multivariate analysis for RFS
          in all patients. Compared with tumors with high PAI-2 levels, those with
          intermediate and low levels showed a poor RFS with a RHR (95% CI) of 1.30
          (1.14-1.48) and 1.76 (1.38-2.24), respectively. Similar results were
          obtained in the multivariate analysis for OS in all patients. Furthermore,
          uPA and PAI-1 were independent predictive factors of a poor RFS and OS in
          node-negative and node-positive patients. PAI-2 also added to the
          multivariate models for RFS in node-negative and node-positive patients,
          and in the analysis for OS in node-negative patients. uPAR did not further
          contribute to any of the multivariate models. A prognostic score was
          calculated based on the estimates from the final multivariate model for
          RFS. Using this score, the difference between the highest and lowest 10%
          risk groups was 66% in the analysis for RFS at 10 years and 61% in the
          analysis for OS. Moreover, separate prognostic scores were calculated for
          node-negative and node-positive patients. In the 10% highest risk groups,
          the proportion of disease-free patients was only 27 +/- 6% and 9 +/- 3% at
          10 years for node-negative and node-positive patients, respectively. These
          proportions were 86 +/- 4% and 61 +/- 6% for the corresponding 10% lowest
          risk groups of relapse. We conclude that several components of the uPA
          system are potential predictors of RFS and OS in patients with primary
          invasive breast cancer. Knowledge of these factors could be helpful to
          assess the individual risk of patients, to select various types of
          adjuvant treatment and to identify patients who may benefit from targeted
          therapies that are currently being developed.</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>
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