[Detection of microsatellite instability in primary gastric cancer using fluorescence-labelled primers multiplex PCR]

To assess the role of microsatellite instability(MSI) on chromosome 19 in the carcinogenesis of gastric cancer. 26 microsatellite markers on chromosome 19 were amplified by Fluorescence-Labelled Primers Multiplex PCR in 44 paired gastric cancer tissues for MSI. The amplified fragments ran in PAGE gel by ABI 377 sequencer and the gel images were analyzed by GeneScan and Genotyper. Meanwhile, MSI of four of all microsatellite sites were also analyzed using PCR-SSLP-silver stain method. MSI was observed in 22 of 26(84.62%) microsatellite sites. D19S402 showed the highest frequency(22.73%). The total frequency of MSI was 8.3%. In 44 gastric cancer samples, 34(77.27%) cases showed MSI at one or more than one site. MSI, as a possible mechanism of carcinogenesis, might play an important role in human primary gastric cancer. MSI detections will become an integral part of the routine classification of all gastrointestinal tumors in the very near future.