Smac、Caspase-9在食管癌中的表达及与细胞凋亡的关系

目的　探讨caspase-9、Smac蛋白在食管鳞癌中的表达及其与肿瘤细胞凋亡的关系。 方法　采用免疫组化SP法对80例经病理确诊为食管鳞癌病例的癌组织、正常组织及癌旁组织进行caspase-9和Smac蛋白半定量免疫组化分析，用TUNEL法检测石蜡切片中肿瘤细胞凋亡情况。 结果　（1）Smac 、caspase-9在食管正常组织、鳞癌组织、癌旁组织的阳性表达率分别为92.50%，63.75%，77.50%和85.00%，58.75%，72.5%，差异均有统计学意义。（2）Smac表达阳性的51例中，Caspase-9蛋白阳性表达47例，占92.16%（47/51），两者表达有极强的关联性。(3)在Smac蛋白表达阳性组平均癌细胞凋亡率(19.186±1.331)，明显高于Smac蛋白表达阴性组(10.316±1.661)；与Caspase-9蛋白表达阳性组比较无差异。47例　Smac 与Caspase-9蛋白共表达阳性组平均细胞凋亡率（26.819±1.273）明显高于Smac 与Caspase-9蛋白共表达阴性组（6.154±1.631）。 结论　Smac、caspase-9在食管癌中的表达呈明显的正相关，二者共同参与了食管鳞癌的发生、发展，在食管癌细胞的凋亡中发挥正反馈调节作用。

Expression of Smac and Caspase-9 and its relationship with apoptosis in esophageal squamous cell carcinoma

Objective　To investigate the expression of Second mitochodria-derived activator of caspase (Smac) and Caspase-9 in esophageal squamous cell carcinoma (ESCC) and its relationship with apoptosis. Methods　Immunochemistry(SP-method) was applied in semi-quantitive analysis on protein of Smac and Caspase-9 in cancer tissues, normal tissues and adjacent tissues of 80 cases of ESCC. Apoptosis of tumor cells in paraffin sections was observed with the method of TUNEL.　Results　(1) The positive expression rate of Smac were 92.50% , 63.75%and 77.50% in normal tissues, ESCC tissues, adjacent tissues and respectively, the positive expression rates of Caspase-9 were 85.00%, 72.50% and 58.75% respectively in normal tissues, ESCC tissues and adjacent tissues. The differences were of statistical significance. (2) 47 cases with Caspase-9 positive expression were detected in 51 cases of ESCC with positive expression of Smac, accounting for 92.16%; the correlation between Smac and Caspase-9 expression was strong and positive. (3) The average apoptotic index (AI%) in Smac positive group (19.186±1.331) was apparently higher than that in Smack negative group (8.316±1.661), which has no significant difference from the Caspase-9 positive expression group. The average apoptotic index of 47 cases with positive co-expression of Smac and Caspase-9 was statistically significantly higher than that with negative expression of Smac and Caspase-9.　Conclusions　The expression of Smac and Caspase-9 protein are positively related and both of them are involved in the genesis and development of ESCC, which also play a positive feedback regulation in the apoptosis of ESCC cells.