Aberrant methylation of CpG island in 5′ promoter region of p16 gene and its role in diagnosis of pancreatic cancer / 第二军医大学学报

ABSTRACT

Objective: To investigate the aberrant methylation of CpG island in 5′ promoter region of p16 gene in the pancreatic juice and its value in diagnosis of patients with pancreatic cancer. Methods: Pure pancreatic juice(PPJ) was collected from the pancreatic duct by a nasopancreatic tube put under endoscopic retrograde cholangiopancreatography (ERCP). Cytological examination was performed by H-E staining in pure pancreatic juice. Aberrant p16 methylation was detected using the methylation-specific PCR (MSP) in the PPJ. Results: The sensitivity, specificity, positive predictive value, negative predictive value and accuracy cytological examination in diagnosis of pancreatic cancer were 40%, 100%, 100%, 45.4% and 60.0%, respectively. The DNA sequences were successfully extracted from the PPJ of 30 patients with pancreatic diseases and were subjected to MSP. Seven(35%) of the 20 cases with pancreatic cancer showed aberrant methylation of p16 gene. No aberrant methylation was detected in the pancreatic juice samples of patients with chronic pancreatitis and mucinous cystoadenocarcinoma of pancreas. When cytological examination combined with p16 methylation detection, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy for diagnosis of pancreatic cancer were 55%, 100%, 100%, 52.6% and 70%, respectively. Conclusion: Pancreatic juice collected by nasopancreatic drainage during ERCP can be used for molecular analysis. Detection of aberrant methylation of p16 gene in pancreatic juice combined with cytological examination is a better method for diagnosis of pancreatic cancer.