| Pancreatic adenocarcinoma is a kind of the digestive carcinoma, and can results in serious problems to human health. Most cases are discovered at late stage when they are not curable by surgery due to lack of typically clinical symptoms and sensitive detecting methods. The five-year survival rate is less than 5%. As other tumors , the mechanism of pancreatic carcinogenesis has not been clear. Recent studies showed that aberrant cell cycle is strongly related to the occurrence and development of cancers. Bcl-2(B-cell lymphoma/leukemia-2) protein acts as an important apoptosis-inhibiting protein. p53 protein acts as an important regulatory protein in the cell cycle. Bcl-2 can inhibit p53-triggered apoptosis, whereas p53 protein can induce apoptosis through transcriptional modulation of Bcl-2 and Bax and through the inhibition of a potent Bcl-2 gene promoter. PCNA (proliferating cell nuclear antigen), a cyclin, is the auxiliary protein of DNA polymerase-δ , and is required during DNA replication. In order to investigate the possible mechanism of pancreatic carcinogenesis and the clinical value of Bcl-2, p53 and PCNA in pancreatic carcinoma, an immunhistochemical Streptavidin-Peroxidase(SP) method was used to examine the expression of the three kinds of protein.Material and Methods: (1)32 surgical resected primary pancreatic ductal adenocarcinoma samples and 12 normal pancreatic tissue samples which were adjacent to pancreatic carcinoma but were confirmed pathologically as normal pancreatic tissue as well as 10 benign pancreatic disease samples including 2 pancreatic cystis, 5 chronic pancreatitis and 3 acute pancreatitis samples were collected. All the tissue were fixed in 10% neutral formalin and embedded in paraffin. (2)SP immunohistochemical method was performed on formalin-fixed paraffin samples for the detection of Bcl-2, p53and PCNA. (3) The data were analyzed by software spss10. 0, x2-test or exact probability, t or t ' -test was used to compare difference between groups. A Pvalue of less than 0. 05 was considered statistically significant.Result: (1) In pancreatic carcinoma, the immunhistochemical staining of Bcl-2 protein was localed in the cytoplasm of pancreatic carcinoma cells with positive rate of 46.9%. The pattern of staining was focal or diffuse. In normal pancreatic tissue and pancreatic benign disease, the positive rate of Bcl-2 were 25. 0% and 20. 0% respectively. There were no significant differences of the expression Bcl-2 among the three groups (P>0. 05) . In pancreatic carcinoma, the positive rates of Bcl-2 in the well-differentiated, middle-differentiated group was 61. 9% and in poorly-differentiated group was 18. 2%. There were significant differences of the expression Bcl-2 between the two groups (P<. 05) . The frequency of Bcl-2 expression in stage I ~ II and stage III~IV were 63.2% and 23.1% respectively. Significant differences were found between the two groups (P<0. 05) . In the group with lymph node metatasis and the group without lymph node metatasis, the positive rates of Bcl-2 expression were 11.1% and 60.9% respectively. There were significant differences between the two groups (P<0. 05) . (2) Positive staining of p53 protein was mainly located in the nucleus of pancreatic carcinoma cellswith the positive rate of 43. 8%. The pattern of staining was focal or diffuse. In normal pancreatic tissue and pancreatic benign disease, the immunohistochemical staining of p53 protein were not found. p53 protein expression was found to be significantly elevated in the pancreatic carcinoma compared with normal pancreatic tissue and pancreatic benign disease (P<0. 05) . According to histological grade of pancreatic carcinoma , 32 cases of pancreatic carcinoma were divided into well-differentiated , middle-differentiated group and poorly-differentiated group. The positive rates of p53 expression were 38. 1% and 54.5% respectively. There were no significant differences of the expression p53 between the two groups (P>0. 05) . The positive rates of p53 protein expression in stag...
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