Evaluation of microsatellite instability, MLH1 expression and hMLH1 promoter hypermethylation in colorectal carcinomas among Tunisians patients.

Background: About 10% to 15% of sporadic colorectal cancers demonstrate high level of microsatellite instability that is generally associated with aberrant methylation of hMLH1 promoter.

Aim: To investigate the association between MSI status, hMLH1 protein expression and methylation status of the hMLH1 promoter in a cohort of Tunisian sporadic colorectal cancer.

Methods: Expression of MLH1 and MSH2 was determined by immunohistochemistry and the MSI status was analysed by microfluid-based on-chip electrophoresis.

Loss of galectin-3 expression in mucinous colorectal carcinomas is associated with 5'CpG island methylation in Tunisian patients.

The β-galactoside-binding protein galectin-3 (gal-3) has pleitropic biological functions and has been implicated in cell growth, differentiation, adhesion, RNA processing, apoptosis, and malignant transformation. To investigate the pattern of inactivation of the gal-3 gene (LGALS3) in colorectal cancers (CRC), we studied a series of Tunisian patients with CRC to identify abnormal methylation in LGALS3 promoter using a methylation-specific PCR. We also examined the gal-3 gene expression by reverse transcription-PCR and the expression of gal-3 protein by immunohistochemistry.

[P73 gene expression in colorectal adenocarcinoma: a prognostic or etiopathogenetic factor?].

Background: The p73 gene encodes a nuclear protein that is highy homologous to p53. p73 also shares some common functions with p53 protein indicating that p73 gene is a p53-like tumor suppressor.

Aim: In this study, we examined by immunohistochemestry the p73 expression on 120 cases of colorectal carcinomas and evaluated its implication in carcinogenesis.