RESUMO
Objective To investigate the incidence and clinicopathologic significance of MSI in breast caner.Methods 40 paired sporadic invasive breast cancer were collected.Genomic DNA was extracted from live sample.Twelve microsatellites on chromosomes 2p,3p,5q,6q,16q,17q were amplified for MSI,respectively,by polymerase chain reaction(PCR)with designed primers and detecting after polyacrylamide gel electrophoresis.Results MSI in 15 out of 40(35%)of the carcinomas were observed.There was no MSI in benign hyperplasia.MSI was mainly located at D3S1766,D2S2739 and TP53 in the breast cancer.The incidence rate of MSI in breast cancer is associated with the degree of carcinoma differentiation.Conclusions Microsatellite instability might play a role in the early stage during multistep breast carcinogenesis.MSI indicated poor histologic differentiation in breast carcinoma.D3S1766,D2S2739 and TP53 might be the sensitive sites to detect MSI in breast carcinoma transformation.