FREQUENT GAIN OF COPY NUMBER ON THE LONG ARM OF CHROMOSOME-20 IN HERMAN PANCREATIC ADENOCARCINOMA

We have used comparative genomic hybridization (CGH) to survey genomic regions with aberrant copy numbers of DNA sequences in pancreatic ade nocarcinoma. In 12 cell lines and 6 primary tumors from 18 patients wi th pancreatic adenocarcinomas, highly frequent losses (>60%) were obse rved on chromosome arms 6q, 9p, and 18q and the Y chromosome. Moderate ly frequent losses (40-60%) were observed on chromosome arms 3p, 4q, 8 p, and 21q. Interestingly, these samples showed extremely high frequen cies of increases in copy numbers of DNA sequences on the long arm of chromosome 20 (15/18, 83%). We further analyzed five cell lines by flu orescence in situ hybridization (FISH) with probes on chromosome 20 to define the increase in copy number more accurately, and we found that 20q was increased to between 5 and 8 copies per cell. These results s uggest the existence of an oncogene or oncogenes on 20q that play a ro le in the development and/or the progression of pancreatic carcinogene sis. (C) 1997 Wiley-Liss, Inc.