TELOMERASE ELEVATION IN PANCREATIC DUCTAL CARCINOMA COMPARED TO NONMALIGNANT PATHOLOGICAL STATES

Telomerase activity was measured in surgically resected tissues of 20 human pancreatic ductal carcinomas, 12 adenomas, 5 pancreatitis tissue s, 14 normal pancreatic ducts, and 13 normal pancreatic tissues (prima rily made up of acinar cells) using a PCR-based telomerase assay, Rela tive telomerase activity was expressed as the equivalent telomerase in tensity of the number of cells of a human pancreatic cancer cell line, MIA PaCa-2, per microgram of protein in the tissue samples, The media n value (25th percentile, 75th percentile) of relative telomerase acti vity in pancreatic carcinomas was 13.2 (3.58, 244), which was signific antly higher relative to normal tissues, normal ducts, pancreatitis ti ssues, and adenomas (P < 0.0001), When the cutoff value of relative te lomerase activity was set at 1.00 and 3.00, the positivity rates of te lomerase activity in pancreatic ductal carcinomas were 100 and 80%, re spectively, Some of the adenoma samples displayed a weak telomerase la dder, However, when semiquantitatively analysed, the relative telomera se activity of all adenoma tissues was less than 1.00 equivalent cells per microgram protein of the tissues, which was equivalent to the val ues encountered in normal ducts, Thus, our results indicate that react ivation of telomerase may occur at a late stage of pancreatic ductal c arcinogenesis, Therefore, telomerase may be a specific marker for dist inguishing pancreatic cancer from pancreatitis and adenomas.