Studies On Eary Diagnosis Of Human Pancreatic Carcinoma Using Genetic Diagnosis In Pancreatic Juice And Pancreatic Duct Brushing——detection Of Mutations Of K-ras And DPC4 In Exon8 And Exon11 And Telomerase Activity

Pancreatic carcinoma (PC) is a dismal disease with increased morbidity. The early diagnosis of PC made by radiological examinations and measurement of tumor markers is extremely difficult. Therefore, most patients with PC are not diagnosed until the advanced stage of the disease. The prognosis of this cancer is very poor with less than 20% of 1ear postoperative survival rate and less than 5% of 5ear survival rate. Recently, it has been reported that genetic alterations were found during the development of PC. Point mutation in the Kas gene at codon 12 may be detected in about 90% of the PC tissues. Moreover, several studies demonstrated that detection of Kas mutations in pure pancreatic juice (PPJ) was useful for diagnosis of PC Telomerase activity has been detected in 85?0% of human tumor tissues and cells, whereas most normal somatic tissues contain no detectable telomerase activity. DPC4 as a candidate tumor suppressor gene was mutated in more than 50% of primary PC. They play an important role during the carcinogenesis and development of this lethal disease. The aim of this study is to investigate the value of these abnormalities in the diagnosis of PC. 1. PointnutatianofKasatcodonl2 inpancreaticjuicefrc,n patients with pancreatic carcinoma and pancreatitis. Kas point mutation was detected using the polymerase chain reaction and restriction fragmentength polymorphism (PCRFLP) in PPJ collected from the pancreatic duct through 6 a nasopancreatic tube put under endoscopic retrograde cholangiopancreatography (ERCP). 12 patients had PC and 8 patients had chronic pancreatitis (CP). The average PPJ obtained from patients with pancreatic carcinoma and chronic pancreatitis was 86 ?27m1 (56?40m1) and 102 ? 24m1(73?50m1),respectively. The positivity of K梤as point mutation in PPJ was 58.3%(7/12) in patients with PC and 12. 5%(l/8) in patients with CP. By the same time, cytological examination and CEA measurement in PPJ were performed. Positive cytological results were obtained in 1 of 12 patients of PC (8. 3%). The CEA levels in PPJ were significantly higher in patients with pancreatic cancer (49.04?9.O7ng/ml) than those with pancreatitis (18.84?2.88ng/ml). K梤as point mutation was found in 73.9%(17/23) of pancreatic tissues surgically resected, and in 10%(l/l0) of the adjacent noncancerous tissue. The results here suggest that PPJ could be easily and safely obtained using nasopancreatic drainage during ERCP . The CEA levels in the PPJ were provided useful marker for differential diagnosis of the pancreatic cancer from chronic pancreatitis. Kas point mutation at codon 12 in pancreatic juice indicate that patients is at high risk for the development of pancreatic cancer. 2. Telomerase activity and Telomerase gene expression in pancreatic carcinoma Telomerase is a key enzyme with regard to immortalization of cancer cells. Telomerase activity was increased in various human malignant neoplasms. In this part, telomerase activity was detected in human pancreatic carcinoma. The samples were obtained from 27 patients undergone pancreatic duct brushing (PDB) during ERCP and 23 patients undergone operative resection of PC. Telomerase activity was measured by the polymerase chain reaction and telonEric repeat anplification protocol assay (PCR桾RAP桬LISA). The expression and...