Study On Expression Of COX-2 And PTEN Genes In Colorectal Carcinoma

Objective: To investigate the expressions of COX-2 and PTEN in colorectal carcinoma and their correlations with the bionomics of colorectal carcinoma.Methods: The expressions of COX-2 and PTEN protein were deter- mined by immunohistochemical staining (Streptavidin-Peroxidase/ S-P method) in the tissues of 48 colorectal carcinoma, 20 colorectal adenomas and 20 normal colorectal mucous .Based on dying strength and masculine cell population ,the results were divided as"-,+,++,+++". The data was analyzed by software SPSS11.5. The difference of COX-2 and PTEN expression in the different pathological classifications of colorectal carcinoma was analyzed with Chi-square Test. Spearman method was used to analyze the relationship between COX-2 and PTEN expression in the colorectal carcinoma.Results: (1).The positive staining of COX-2 mainly located in cytoplasm. The rate of COX-2 expression was 79.2% in colorectal carci- noma group, 50.0% in colorectal adenoma and 15.0% in the normal colore- ctal mucous membrane group respectively. There were significant differences among the there groups (P<0.05). The expression of COX-2 had relationship with lymphatic metastasis and Dukes stages, but had no relationship with sexuality, age,size ,position and histological differentia- tion. The rate of COX-2 expression was 91.7% in colorectal carcinoma group with lymphatic metastasis and 66.7% in colorectal carcinoma group without lymphatic metastasis. A significant difference was observed between the two groups (P<0.05). The rate of COX-2 expression was higher in the group of Dukes C and D stages than that in the group of Dukes A and B stages (P<0.05).(2).The positive staining of PTEN mainly located in the nucleus of colorectal carcinoma tissues. The rate of PTEN expression was 33.3% in colorectal carcinoma group, 60.0% positive expression in the colorectal adenoma and 95.0% positive expression in normal colorectal mucous membrane group respectively. There were statistically significant differences among the there groups (P<0.05). The expression of PTEN had relationship with lymphatic metastasis and Dukes stages, but had no relationship with sexuality, age, size, position and histological differentia- tion. The rate of PTEN expression was 14.6% in colorectal carcinoma group with lymphatic metastasis and 50.0% in colorectal carcinoma group without lymphatic metastasis. A significant difference was observed between the two groups (P<0.05).The rate of PTEN expression was 50.0% in the group of Dukes A and B stages and 19.2% in the group of Dukes C and D stages. The positive expression rate of A and B stages was higher than that of C and D stages (P<0.05). (3).Of the 38 specimens with positive COX-2,9 had the positive expression of PTEN; of the 10 specimens with negative COX-2,7 had the positive expression of PTEN. There was a negative correlation between COX-2 and PTEN(r=-0.326, P<0.05).Conclusion:(1). COX-2 is highly expressed in colorectal carcinoma tissues,but it is lowly expressed in adenoma and normal tissues. The expression of COX-2 is related to lymphatic metastasis and Dukes stages. But it has no relationship with sexuality, age,size ,position and histological differentiation. (2). PTEN is lowly expressed in colorectal carcinoma and colocrectal adenoma tissues, but it is highly expressed in normal colorectal mucous membrane. The expression of PTEN has relationship with lymphatic metastasis and Dukes stages ,but it is not related to sexuality, age,size ,position and histological differentiation. (3). COX-2 and PTEN play an important role in the carcinogenesis of colorectal carcinoma. The expression of COX-2 is negative related to that of PTEN in colorectal carcinoma tissues.