凋亡相关基因caspase-9,bax及bcl-2在大肠癌中的表达及其意义

Expression and Significance of Apoptosis Related Gene caspase-9, bax and bcl-2 in Colorectal Adenocarcinoma and Carcinoma

目的探讨凋亡相关基因easpase-9,bax和bel-2在大肠癌中的表达及其在大肠癌发生、发展中的可能作用及相互关系。方法应用免疫组化S-P法检测20例正常大肠黏膜、48例大肠腺瘤及56例大肠癌中的caspase-9、bax和bcl-2蛋白的表达。用TUNEL 法检测细胞凋亡。结果正常大肠黏膜、大肠腺瘤和大肠癌中caspase-9的阳性表达率分别为5．00％、33．33％、64．29％,其表达率在三者间差异有显著性(P<0．01)。bax在三种组织中的表达率分别为5．00％、35．42％、62．50％,三者间差异有显著性(P<0．01)。bcl-2 在三者中的阳性表达率分别为15．00％、87．50％、60．71％,三者间差异亦有显著性(P<0．01)。caspase-9,bax和bcl-2的表达与大肠癌的分化程度有关(P<0．01),与Dukes分期无关(P>05)。正常大肠黏膜、腺瘤和大肠癌中细胞凋亡指数差异有显著性(P<0．01),细胞凋亡指数与肿瘤的分化程度有关(P<0．01),与Dukes分期无关(P>0．05)。caspase-9、bax和bcl-2的表达与细胞凋亡指数有密切联系 (P<0．01)。结论肿瘤早期阶段的细胞凋亡异常,可能是大肠癌的发病原因之一。bcl-2和bax通过调节caspase-9参与大肠癌的发生。

Objective To investigate the expression of apoptosis-related gene caspase-9, bax and bcl-2 and their clinical significances in colorectal carcinoma. Methods Expressions of caspase-9,bax and bcl-2 were detected in 56 cases of eolorectal carcinomas,48 cases of colorectal adenomas and 20 cases of normal tissues by the immuohistochemical method. Apoptotic cells are detected by TUNEL method. Results Positivity of caspase-9 was detectable in 5.00% of normal colorectal mucosas, in 33.33% of adenomas and in 64.29% of cancer specimens Positivity of bax was detectable in 5.00% ,35.42% and 62.50%. The bcl-2 expression was detectable in 15.00% ,87.50% and 60.71%. There was significiant difference in the normal colorcctal mucosas,coloreetal adenomnas and colorectal carcinomas （P〈0.01）. The difference of apoptosis index（Al） was significant in normal eolorectal mucosas ,coloreetal adenomas and colorectal carcinomas（P〈0.01）. The expressions of caspase-9, bax and bcl-2 were reversely correlated to Al （P〈0.01）. Conclusion The abnormity of apoptosis are the possible mechanism of the colorectal carcinogenesis bax and bcl-2 may participate apoptosis by regulating easpase-9.