The Influence of Expressions of Cyclin B1 and D1 on Clinicopathologic Prognostic Factors and Survival Rate in Gastric Cancer

PURPOSE: Disturbance in normal cell cycles by cell cycle control factors is an important process of cancer carcinogenesis. The aims of this dissertation were identify the influence of cyclin B1 and D1 on the growth and expression of gastric cancer and their effects on the prognosis. METHOD: The subjects were 128 patients selected from those who underwent gastric surgery for their gastric cancer between January 1995 and December 1998. Immunohistochemical staining was conducted for cyclin B1 and D1 using paraffin embedded tissues, followed by analysis of their protein expressions, possible prognostic factors and survival rate. RESULTS: Cyclin B1 expression was founded in 48 of the 128 patients (37.5%), and that of cyclin D1 in 96 (75%). Both cyclin B1 and D1 showed no statistical significance with T-stage, location of tumors or histologic types. However, for the case of any significance with lymph node metastasis, the higher the N-stage, the greater was the expression of cyclin B1 (P=0.014). For the case of any significance with life term, the Kaplan-Meier method showed the greater the expression of cyclin B1, the shorter the life term (P=0.042). CONCLUSION: An association was indicated between cyclin B1 and lymph node metastasis in gastric cancer, but has no relation with the T-stage, histologic type or location of tumors. Cyclin D1 shows no association with lymph node metastasis, T-stage, histologic type or location of tumors. However, cyclin B1 showed a significant association with the survival rate.

Immunohistochemical Study of p53 Gene Protein and bcl-2 Gene Protein Expression in Gastric Adenocarcinoma

The p53 oncoprotein, a product of the tumor suppressor gene encoded on the short arm of chromosome 17, has been noted in a number of human tumors as a tumor suppressor and some what has been related with cellular apoptosis. Thus, mutant p53 inhibits apoptosis. Like the mutant p53 oncoprotein, the bcl-2 oncoprotein expressed in various epithelial and nonepithelial cells plays a major role in inhibiting cellular apoptosis. To elucidate the role of bcl-2 and mutant p53 oncoprotein expression in gastric adenocarcinomas, immunohistochemical stains were carried out in 60 cases of gastric adenocarcinomas including 10 cases of early gastric cancer. We studied the expression patterns of the bcl-2 and the mutant p53 protein according to age, sex, histologic differentiation, tumor location, tumor size, lymph-node involvement, and depth of tumor invasion. The results were as follows: 1) p53 protein expression was detected in 39 of 60 cases (65%), and bcl-2 protein expression was detected in 29 of 60 cases (48%). 2) The p53 and the bcl-2 expression rates for early gastric cancer were 60% and 50%, and those for advanced gastric cancer were 66% and 40%, respectively. 3) There was no significant correlation of p53 or bcl-2 expression with sex, age, histologic differentiation, tumor location, tumor size, and lymph-node involvement; however, the expression of p53 was correlated with the depth of tumor invasion (p=0.049). Based on the present study, the expression of p53 is thought to be correlated with tumor progression and may be a useful prognostic factor in gastric adenocarcinomas.