CHANGES IN DNA COPY NUMBER IN PRIMARY GASTRIC CARCINOMAS BY COMPARATIVE GENOMIC HYBRIDIZATION

We examined 33 primary gastric carcinomas using comparative genomic hy bridization to detect changes in the DNA copy number and the chromosom al location of these changes. Ninety-four percent (31 of 33) showed 1 or more DNA copy number changes, such as increases at 2p23-p25 (observ ed in 21% of the total cases), 3q26.3-q27 (24%), 7p15 (24%), 9p22-pter (18%), and 13q22-q34 (21%) and decreases at 1p34.2-p36.2 (18%) and Y (52%). Histological examination indicated that increases at 3q26.1-q26 .3 and 7p15 and decreases at 1p36.1-p36.2 and Y were commonly observed in both differentiated and undifferentiated types. Increases at 3q27, 6q23-q25, and 7cen-p14 and decreases at 1p34.2-p35 and 17p12 were pre dominantly observed in the differentiated type, and increases at 2p23- pter, 9p22-pter, and 13q31-qter and a decrease at 6p21.3 were predomin antly observed in the undifferentiated type. In addition, clinical sta ging of tumors showed that increases at 2p23-p25, 7p14-p21, 7q31-q32, and 9p22-pter and a decrease at Y were observed in early-stage tumors, whereas increases at 9q32-q33 and 15q26 were observed only in late-st age tumors. Many of the abnormalities detected in this study were not previously reported in gastric carcinomas. Our comparative genomic hyb ridization results indicate the presence of genetic alterations that m ay play some important role in the development and progression of gast ric carcinomas.