[Screening the hereditary nonpolyposis colorectal cancer by revised Bethesda guideline: a cohort study of 110 cases].

ABSTRACT

OBJECTIVE: To study the value of screening hereditary nonpolyposis colorectal cancer (HNPCC) by the revised Bethesda guideline and the rate of HNPCC in colorectal cancer (CRC). METHOD: Tumor tissues and normal colorectal mucous membrane tissues were collected from 110 successive cases with CRC, 66 males and 42 females, aged 60.8 (26 - 94). Fluorescence multiplex polymerase chain reaction was used to detect the microsatellite instability (MSI). The peripheral blood samples were collected from the patients with MSI, genomic DNA was extracted, and PCR and DNA sequencing were used to detect the germline mutations of hMSH2, hMSH6, and hMLH1. RESULTS: Twenty-three out of the 110 patients (20.9%), 12 males and 22 females, aged 57 (47 - 94), had MSI. Seven germline mutations were found in these 23 MSI patients, accounting for 6.4% among the 110 CRC patients, including 3 cases of hMSH2 mutation, 3 cases of hMSH6 mutation, and 1 case of mutation of hMLH1. CONCLUSION: Screened by revised Bethesda guideline, the rate of MSI CRC is 20.9% and the rate of HNPCC is 6.4%. The missence germline mutations of hMSH2 and hMSH6 are more common in the Chinese patients with CRC.