| Pancreatic carcinoma is a kind of malignant tumor with very poor prognosis,In recent years,the prevalence of pancreatic cancer has been increasing all over the word.About 28000 patients with pancreatic cancer were diagnosed in each year in USA. Pancreatic cancer is the fourth leading cause of malignant tumor death and is the second leading cause of tumor of gut in USA.The incidence of pancreatic cancer was 1.25/105 in Shanghai in 1963 and was 4/105 in 1977 and was 9.4/105 in 1995.Now the incidence of pancreatic cancer has been the seventh or eighth of malignant tumors,which is one of the common malignant tumors.Pancreatic cancer is a dismal disease.The majority of patients with pancreatic cancer are already in advanced stage when they present with symptoms.Although several imaging modalities recently are developed and applied to diagnosis of pancreatic cancer,its prognosis are still very poor and the 5 years survival rate are about 5%.Recently a number of genetic alterations related to pancreatic carcinoma ,for example ,K-ras,DPC4,p16, p53 and telomerase were reported.In particular,point mutations in the K-ras gene at codon 12 may be detected in 75%～100% of the pancreatic cancer tissues.K-ras gene mutation has been found in early pancreatic cancer.So Many researchers detected K-ras gene mutation from clinical samples such as blood,pure pancreatic juice,duodenal lavage fluid,stool,biopsies and they hoped to diagnose pancreatic cancer in early stage.The p53 gene is a tumor suppressor gene.p53 mutations have been reported in 58%(100%(average 78%)of pancreatic carcinoma cell lines,in70%(86% of primary pancreatic carcinomas.There are no p53 mutations in benigh pancreatic diseases.So p53 gene should be used as a marker to diagnose pancreatic cancer.Rearch about p16 gene focused on the deletion and mutation of p16 gene.We do not find rearch about aberrant p16 gene methylation in primary pancreatic cancer and its clinical pathologic significance.We detected K-ras gene mutation,p53 protein expression,aberrant p16 gene methylation in clinical samples.The aim of this study is to investigate the value of these abnormalities in the diagnosis of pancreatic cancer. 1.Point mutation of K-ras gene at 12 codon and expression of p53 protein in pancreatic brush cytologic samples from patients with pancreatic carcinoma and chronic pancreatitis Objective: To investigate the value of detecting K-ras and p53 gene mutations from pancreatic brush cytologic samples in the diagnosis of pancreatic cancer.Methods and materials:The samples were obtained from 44 patients undergone pancreatic duct brushing during ERCP and 28 patients undergone operative resection of pancreatic cancer. We detect p53 protein in cytologic specimens by immunohistochemistry and K-ras gene mutation at 12 codon by PCR-SSCP and compare with cytologic specimens by HE staining.Results: Cytologic samples were obtained successfully from 44 patients with pancreatic diseases.There were no severe complications during ERCP.The positive rate of cytologic examination was 48% in patients with pancreatic cancer,and the cytologic examination was negative in patients with benigh pancreatic diseases. Sensitivity, specificity,accuracy,positive predictive values and negative predictive values of HE staining for pancreatic cancer is 48%, 100%, 70.4%, 100% and 59%. The PCR successful rate of pancreatic exfoliated cell was 100%. K-ras gene mutation rate is 72%(2/14) in patients with pancreatic cancer,which is higher than that of chronic pancreatitis(14%, P<0.05). K-ras gene mutation are not found in pancreatic cystocarcinoma. Sensitivity, specificity, accuracy, positive predictive values and negative predictive values of this method for pancreatic cancer is 72%, 89%, 79.5%,71％and 70.8％.Mutational patterns of K-ras gene in pancreatic brush cytologic samples were the same as that of K-ras gene in tissues samples.p53 protein was detected in 29 pancreatic brush cytologic samples. 10 of 17 cases with pancreatic cancer were positive for p53. All of the cases w...
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