Relationship Between the Alteration of Apoptosis Related Genes and Sensitivity for Radiotherapy and Chemotherapy in Human Cancer

点击翻译按钮获取中文摘要

P53, p21^<WAF1/CIP1>, Bcl-2 and Bax were analyzed in esophageal and colorectal cancer cell lines. p53 and p21^<WAF1/CIP1> were expressed in about 70% and 40% of the cell lines respectively. Bcl-2 was expressed in the majority of the esophageal cancer cell lines and a few colorectal cancer cell lines. Bax was detected in most of the cell lines studied. To search for the determinant factors of radiosensitivity in rectal carcinoma, p53, p21 and Bcl-2 were selected for possible predictive factors for rediosensitivity. Expressions of p53, p21 and Bcl-2were studied in 49 rectal carcinomas by immunohistochemistry before (biopsy specimen) and after (resected specimen) radiatiion and their relations with pathologic effect of rediotherapy. The total dose of rediation was =0Gy in all patients, by 2.5Gy each time, 5 times a week. p53, p21/WAF1 and Bcl-2 expressions were 53.1%, 30.6% and 71.4%, respectively. There was a significant inverse correlation between the expression of p53 and p21. Moderate to marked pathologic effect of radiation was found in 36.7% of the tumors, while others showed little effect. Of the p53 positive tumors, 88.5% were radioresistant, while 65.2% of the p53 negative tumors were radiosensitive. Of the p21 positive tumors, 80,0% were radiosensitive, while 82.4% of the p21 negative tumors were radioresistant. The combinations of p53 (+) and p21 (-) , as a predictor of radioresistance, and p53 (-) and p21 (+), as a predictor of radiosensitivity, enhanced sensitivity (90.0%), specificity (95.4%) and accuracy (93.8%). The expression of Bcl-2 showed no correlation with radiosensitivity. Immunochemically detected p53 and p21 expression can be used as independent predictors for radiosensitivity of redctal carcinoma. The combination of these two factors can make the selection for radiosensitive tumor more sensitive, specific and accurate.