Reduced mRNA expression in paraffin-embedded tissue identifies MLH1- and MSH2-deficient colorectal tumours and potential mutation carriers

摘要: Based on the principle of nonsense-mediated mRNA decay, we sought to identify MLH1 or MSH2-deficient colorectal tumours through relative quantification expression with real-time PCR (RT-PCR) analysis. and MSH2 mRNAs were almost equally expressed as defined by transcript ratio (mean 1.41) in microsatellite stable, mismatch repair (MMR) proficient (n = 16). A close correlation between loss protein MMR–mRNA levels was found highly instable (MSI-H) deficient MSH2. MLH1/MSH2 low 11 sporadic nine hereditary MLH1-deficient carcinomas 0.51), whereas high 17 non-polyposis cancer (HNPCC) associated 6.8). Notably, normal tissues HNPCC patients mutations, ratios significantly elevated (ratio > 2.0) compared mucosa MMR-proficient (27 32 < 2.0; p 0.00113). Analysis B-lymphocytes proven MMR gene mutation confirmed these findings. In conclusion, RT-PCR allows formalin-fixed paraffin-embedded tissue. Furthermore, this approach enables haploinsufficiency due decay tissue from carrying germline mutations may be useful for identification asymptomatic carriers pathogenic mutations.