The Immunohistochemical Expression of E2F-1 Protein and DNA Topoisomerase II-alpha E2F-1 Protein in Colorectal Cancer and Their Relationship with Clinicopathologic Factors

PURPOSE: E2F-1 is a transcriptor that converts G1 to S in the cell cycle, and Topoisomerase II-alpha is a key enzyme in the metabolism of DNA, and an indicator of cell replication. The purpose of this study was to evaluate the clinical validity of E2F-1 and Topoisomerase II-alpha as prognostic factors in colorectal cancer. METHODS: The expressions of E2F-1 and Topoisomerase II-alpha were studied immunohistochemically using tumor specimen sections fixed with formalin and paraffin-embedded for 84 cases of colorectal cancer. The correlation between E2F-1 and Topoisomerase II-alpha expressions, and their relationship with the clinicopathological factors, such as tumor differentiation, tumor invasion, lymph node metastasis and tumor stage were investigated. RESULTS: Of the 84 specimens, 43 (51.2%) were immunohistochemically negative for E2F-1, and 41 (48.8%) were positive. The expression of E2F-1 correlated with poor tumor differentiation, increased lymph node metastasis and high tumor stage. The expression of Topoisomerase II-alpha also correlated with poor tumor differentiation, increased lymph node metastasis and high tumor stage. The E2F-1 and Topoisomerase II-alpha expressions indices were significantly correlated. CONCLUSION: These results suggest that the expressions of E2F-1 and DNA Topoisomerase II-alpha may play a role as a prognostic factor for colorectal cancer, but further studies will be required for its comfirmation.

Expression of p27Kip1 Protein and Correlation with Clinicopathologic Factors in Colorectal Carcinoma

PURPOSE: The p27Kip1 gene has been recognized as a negative regulator of the cell cycle and a potential tumor suppressor gene. Reduced expression of the p27Kip1 protein has been reported in several human tumors and has been associated with a poor prognosis in breast, lung, colon, prostate, bladder, esophageal and gastric cancers. In the present study, we assessed p27 expression in patients with colorectal cancer in relation to their clinicohistological parameters. METHODS: We investigated p27 expression in 80 patients with colorectal cancers using immunohistochemical staining and the results were analyzed regarding the survival and clinicopathological parameters. RESULTS: Among 80 cases of clolorectal carcinomas, p27Kip1 expression was detected in the nuclei of tumor cells in 48 cases (60%). With the exception of differentiation (p<0.01), no significant correlation was found between p27Kip1 and TMN stage, lymph node metastasis, depth of tumor invasion or overall survival. CONCLUSION: The results suggest that reduced expression of p27Kip1 protein plays a role in the differentiation of colorectal carcinoma and may be a potential prognostic factor. But, more studies are reqired in order to determine whether p27Kip1 protein expression is a clinically valuable prognostic factor.