Loss of E (epithelial)-cadherin expression has been previously documented in sporadic colorectal carcinomas (SCRCs), but not as a consequence of mutations or allelic loss. In this study, the methylation status of the E-cadherin promoter was examined by utilizing the methylation-specific polymerase chain reaction (MSP) assay in 63 primary SCRCs and paired adjacent normal tissues. This was correlated with E-cadherin expression at both the RNA and the protein levels using multiplex reverse transcription (RT)-PCR and immunohistochemistry (IHC), respectively. Data were associated with the patients' clinicopathological features. Methylated alleles were present in 34/61 (56%) of the samples examined. Decreased E-cadherin mRNA expression was demonstrated in 29/61 carcinomas (47.5%) and was significantly associated with lymph node (LN) metastases (p = 0.03, Kruskal-Wallis) and tumour stages Astler-Coller B1 and B2 (p = 0.01, chi2 ). E-cadherin IHC expression was significantly associated with the absence of LN metastases (p = 0.01, chi2 ) and tumour stages Astler-Coller B1 and B2 (p = 0.002, Kruskal-Wallis) in 28/63 (44.4%) of the samples examined. Twenty-three out of 29 (79.3%) samples with decreased mRNA expression and 20/33 (60.6%) with detected protein expression revealed methylated (p = 0.03, Kruskal-Wallis) and unmethylated (p = 0.01, Kruskal-Wallis) alleles, respectively. In agreement with previous work demonstrating that somatic mutations and loss of heterozygosity of the E-cadherin gene are rare or absent in the majority of SCRCs studied so far, this study reports a consistent and uniform decrease or absence of E-cadherin expression, associated with aberrant methylation, in the majority of carcinomas examined, suggesting an epigenetically mediated loss of E-cadherin function in these carcinomas. Copyright

Colorectal cancer, E-cadherin, Immunohistochemistry, Methylation, RT-PCR
dx.doi.org/10.1002/path.1237, hdl.handle.net/1765/61598
Journal of Pathology
Department of Molecular Genetics

Garinis, G.A, Peros, G, Menounos, P.G, Spanakis, N.E, Papadopoulos, K, Karavitis, G, … Manolis, E.N. (2002). Hypermethylation-associated transcriptional silencing of E-cadherin in primary sporadic colorectal carcinomas. Journal of Pathology, 198(4), 442–449. doi:10.1002/path.1237