COMPARATIVE GENOMIC HYBRIDIZATION REVEALS DIFFERENCES IN DNA COPY NUMBER CHANGES BETWEEN SPORADIC GASTRIC CARCINOMAS AND GASTRIC CARCINOMASFROM PATIENTS WITH HEREDITARY NONPOLYPOSIS COLORECTAL-CANCER

Comparative genomic hybridization was used to search for DNA copy numb er changes in samples of gastric cancer from 12 hereditary nonpolyposi s colon cancer (HNPCC) patients and in samples of sporadic gastric car cinoma from 13 patients. The gastric cancer samples from HNPCC patient s showed gains affecting 19q, Xp, and whole chromosome 22, each in a s ingle patient. Neither high-level amplifications nor losses of DNA cop y number were detected. On the other hand, 10 of the 13 (77%) sporadic gastric carcinoma samples had multiple DNA copy number changes. The m ost frequent gains occurred with minimal common overlapping regions at 1q22-q31, 8q23-qter, 17p11.2-q22, and 20q, all at a frequency of 31%. High-level amplifications were also seen at 17q21 in three cases (23% ). Losses were rare, and the most frequent loss was with a minimal com mon overlapping region at 4q32 (23%). This suggests that multiple DNA copy number changes are needed for the development of sporadic gastric carcinoma but not for gastric carcinoma in HNPCC patients. (C) Elsevi er Science Inc., 1998.