LOSS OF CHROMOSOME 18Q IS AN EARLY EVENT IN PANCREATIC DUCTAL TUMORIGENESIS

Cytogenetic and molecular studies demonstrated that pancreatic cancer frequently shows specific chromosomal abnormalities, such as losses of 9p, 17p, and 18q, and gains of 8q and 20q. We have analyzed alteratio ns in the copy number of specific chromosomal regions in cells from th e pancreatic juices of 32 patients with various pancreatic disorders b y fluorescence irt situ hybridization (FISH) technique to pursue the p ossible clinical use of early diagnosis of pancreatic cancer. None of the chromosomal abnormalities were found in 13 specimens from individu als who had no neoplastic lesions. On the other hand, 12 specimens (63 %) derived from the remaining 19 patients who had neoplastic lesions s howed at least one chromosomal abnormality. Ten of these specimens wer e from pancreatic cancer patients; 7 cases (70%) showed chromosomal ab normalities. AII but one of the 12 tumors with chromosomal abnormaliti es had loss of 18q. Furthermore, we detected a tumor in one patient in whom the routine cytological method and endoscopic retrograde chorang iopancreatography found nothing. Based on the results by FISH, we pel formed endoscopic ultrasonography and found a small serous cystadenoma in this patient. These results indicate that: (a) FISH analysis of ce lls from pancreatic juices obtained during endoscopic retrograde chora ngiopancreatography is quite useful for detecting pancreatic ductal tu mors; and (b) loss of chromosome 18q is one of the early genetic chang es that provide very useful information in diagnosing pancreatic neopl asias.