Semi-quantitative analysis of telomerase in pancreatic ductal adenocarcinoma

Using a polymerase chain reaction-based amplification assay, we measured telomerase activity in surgically resected pancreatic ductal carcinomas (n = 16 cases) and normal ducts (n = 6), comparing findings with the telomerase activity of a human pancreatic cancer cell line, MIA PaCa-2, as a standard, i.e., relative telomerase activity was determined. Telomerase activity was expressed as the equivalent telomerase intensity of the number of cells of MIA PaCa-2 per microgram protein of tissue samples. The median value for telomerase activity in normal pancreatic ducts was 0.13 and the 25th and 75th percentile were 0.01 and 0.76. The median value for telomerase activity in pancreatic ductal adenocarcinoma was 34.7 (25th percentile, 4.98; and 75th percentile, 296), significantly higher than that of normal ducts (P < 0.001). When the cut-off value was set at 1.0 and 3.0, the telomerase positivity rate of pancreatic ductal adenocarcinomas was 100% and 81.3%, respectively. Telomerase may be specific marker for pancreatic ductal carcinomas.