Detection of telomerase activity in biopsy specimens for diagnosis of biliary tract cancers

Background: Telomerase activity is detectable in more than 85% of primary c ancers. We determined telomerase activity in biopsy specimens obtained from biliary tract cancers to evaluate the clinical application of telomerase a ctivity detection in combination with p53 immunostaining and routine histol ogic examination. Methods: Biospy specimens obtained during percutaneous transhepatic cholang ioscopy from 13 patients with cholangiocarcinoma, 3 patients with gallbladd er carcinoma, and 4 patients with intrahepatic bile duct stones were evalua ted by routine histologic examination, p53 Immunostaining, and telomerase a ctivity. Semiquantitative determination of telomerase activity was performe d using a fluorescence-based telomeric repeat amplification protocol. Results: Thirteen of 16 specimens of malignant tissue had detectable telome rase activity, whereas no specimen of nonmalignant tissue had detectable te lomerase activity. A p53 overexpression was recognized by immunostaining in 9 of 16 samples with cancers. Combining both telomerase activity and p53 o verexpression resulted in the detection of all cancer with a sensitivity of 100%. There were no false-positive results by either modality (specificity 100%). Conclusions: The detection of telomerase activity in biopsy specimens and p 53 overexpression in combination with routine histologic examination may im prove the diagnosis of biliary tract cancers.