Biallelic inactivation of hMLH1 by hypermethylation and loss of heterozygosity in non-small cell lung cancer

Abstract   OBJECTIVE To investigate the mechanism of hMLH1 deregulation in non-small cell lung cancer (NSCLC). METHODS A genetic and epigenetic study of the hMLH1 gene was performed using surgical primary tumors from 40 NSCLC patients and their corresponding noncancerous tissues. The molecular alterations examined included promoter methylation by Hpa II/Mpa I- based PCR analysis, loss of heterozygosity (LOH) by D3S1621 locus PCR-electrophoresis-silver staining, as well as the loss of protein expression by immuno-histochemical analysis.