直肠癌自发性细胞凋亡、P53蛋白表达和放射敏感性关系的研究

目的:探讨直肠癌自发性细胞凋亡指数(SAI)、P53蛋白表达水平和放射敏感性的关系.方法:对36份直肠癌活检标本分别采用TUNEL和免疫组化法检测(SAI)和P53蛋白基因表达,对放疗后手术切除标本进行放射敏感性测定,观察其与SAI、P53蛋白表达的关系.结果:放疗前直肠癌组织均能检测到细胞凋亡,平均SAI(0.98±0.32)%;SAI与P53蛋白阳性表达率呈负相关(r=0.72,P＜0.05);高凋亡指数组(SAI＞0.98%)放射敏感性明显高于低凋亡指数组(SAI＜0.98%)(P＜0.05);P53蛋白阳性表达率与放射敏感性呈负相关.当SAI＞0.98%,P53(-)时,放疗敏感性明显增高.结论:SAI和P53与直肠癌放射敏感性密切相关,是直肠癌放射敏感性的两个重要预测因素.

Relationship between apoptosis index,expression of P53 and radiosensitivity of rectal carcinoma

Objective:To investigate the correlation between the levels of the spontaneous apoptosis index(SAI),expressions of P53 and the radiosensitivity of rectal carcinoma.Methods:Thirty-six patients with rectal carcinoma who received preoperative radiotherapy were registered in this study.Specimens were obtained by biopsy before irradiation and after operation.The apoptotic index(AI) of each tissue specimen was evaluated by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphophate nick-labling (TUNEL) assay and expressed as a percentage,Immunohistochemical evaluation for P53 and the radiosensitivity of the tumor was also peformed.Results:Consistent low levels of spontaneous apoptosis were observed in all specimens evaluated,the mean AI of spontaneous apoptosis was 0.98% /-0.31%;There was an inverse correlation between SAI and the expression of P53 protein(r=0.72,P<0.05);The radiosensitivity of the group of SAI>0.98% was significantly higher than that of SAI<0.98%(P<0.05);When the expression of P53 and SAI were considered simultaneously,the association with the radiosensitivity was highly significant.Conclusion:This study indicates that there is relationship between SAI and P53 expression and radiosensitivity of rectal cacinoma;SAI and P53 are two of the potential factors which forecasting the radiosensitivity of rectal carcinoma.