A highly sensitive and quantitative telomerase activity assay with pancreatic juice is useful for diagnosis of pancreatic carcinoma without problems due to polymerase chain reaction inhibitors: analysis of 100 samples of pancreatic juice from consecutive patients.
BACKGROUND
Early detection of pancreatic carcinoma is difficult even with current diagnostic tools. Novel biomarkers and detection techniques are urgently needed. Telomerase activity is a promising diagnostic marker. However, the conventional telomeric repeat amplification protocol (TRAP) assay is not suitable for clinical application because of its complexity, time-consuming nature, and the effects of polymerase chain reaction (PCR) inhibitors in samples leading to difficulties in quantification.


METHODS
The authors used a hybridization protection assay in combination with TRAP (TRAP/HPA) to investigate the effects of PCR inhibitors in pancreatic juice on quantification of telomerase activity. They analyzed 117 consecutive samples of pancreatic juice to determine the feasibility of TRAP/HPA for diagnosis of pancreatic carcinoma.


RESULTS
The authors found that TRAP/HPA was 1000-fold more sensitive than the conventional TRAP assay, and that the effects of PCR inhibitors could be avoided by diluting samples. In a large analysis of pancreatic juice samples with TRAP/HPA, 17 samples were excluded from the final analysis because of insufficient follow-up periods or inadequate treatment of the samples. Relative telomerase activity (RTA) in samples from patients with pancreatic carcinoma was significantly higher in comparison to samples from patients with pancreatitis and 13 (61.9%) of 21 samples from patients with pancreatic carcinoma showed high RTA (> 4 U). Meanwhile, high RTAs were observed in 4 of 35 (11.4%) samples from patients with intraductal papillary mucinous tumor and in 1 of 40 samples (2.5%) fom patients without malignant disease.


CONCLUSIONS
TRAP/HPA accurately evaluated weak telomerase activity in pancreatic juice samples without the problem due to PCR inhibitors. This large analysis of nonselected pancreatic juice samples suggested that TRAP/HPA is a promising approach for the diagnosis of pancreatic carcinoma.
Department of Surgery and Oncology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Kenoki
K
Ohuchida
Kazuhiro
K
Mizumoto
Nami
N
Ishikawa
Norihiro
N
Sato
Eishi
E
Nagai
Koji
K
Yamaguchi
Hideki
H
Takaishi
Toshinori
T
Ide
Masao
M
Tanaka
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001681:Biological Assay / Q000379:methods*; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis* / Q000201:enzymology / Q000473:pathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D017403:In Situ Hybridization / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010189:Pancreatic Juice / Q000201:enzymology*; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000201:enzymology / Q000473:pathology; D010195:Pancreatitis / Q000201:enzymology / Q000473:pathology; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D019098:Telomerase / Q000032:analysis* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; D019098:Telomerase