Y Wang1, W Friedl, P Propping. 1. Jiangsu Institute of Cancer Research, Nanjing, Jiangsu 210009 P.R. China.
Abstract
OBJECTIVE: Analysis for germline mutation in mismatch repair genes, hMLH1 and hMSH2, in hereditary nonpolyposis colorectal cancer (HNPCC) patients and presymptomatic diagnosis in HNPCC families. METHODS: Genomic DNA extracted from peripheral blood were subjected to mutation analysis in 35 exons of the hMLH1 and hMSH2 genes by heteroduplex and single strand conformation polymorphism(SSCP) followed by DNA sequencing of aberrant bands in 14 HNPCC and 10 colorectal cancer patients with familial history. RESULTS: Germline mutations were identified in 4/14 HNPCC patients and in 1/10 colorectal cancer patients with familial history, 2 of them in the hMLH1 and 3 in hMSH2 genes. The five mutations are all unique and are predicted to result in nonfunctional proteins by either frameshift (three), nonsense (one) or missense mutation (one) in evolutionarily conserved region. CONCLUSION: HNPPC is closely related to the mutations of mismatch repair genes. Germline mutation analysis for presymptomatic diagnosis in HNPCC could not be limited in the patients meeting clinical diagnosis criteria (Amsterdam 1991).
OBJECTIVE: Analysis for germline mutation in mismatch repair genes, hMLH1 and hMSH2, in hereditary nonpolyposis colorectal cancer (HNPCC) patients and presymptomatic diagnosis in HNPCC families. METHODS: Genomic DNA extracted from peripheral blood were subjected to mutation analysis in 35 exons of the hMLH1 and hMSH2 genes by heteroduplex and single strand conformation polymorphism(SSCP) followed by DNA sequencing of aberrant bands in 14 HNPCC and 10 colorectal cancerpatients with familial history. RESULTS: Germline mutations were identified in 4/14 HNPCC patients and in 1/10 colorectal cancerpatients with familial history, 2 of them in the hMLH1 and 3 in hMSH2 genes. The five mutations are all unique and are predicted to result in nonfunctional proteins by either frameshift (three), nonsense (one) or missense mutation (one) in evolutionarily conserved region. CONCLUSION: HNPPC is closely related to the mutations of mismatch repair genes. Germline mutation analysis for presymptomatic diagnosis in HNPCC could not be limited in the patients meeting clinical diagnosis criteria (Amsterdam 1991).