目的： 探讨大肠腺癌和腺瘤中XIAP（X-linked inhibitor of apoptosis protein)和caspase-3蛋白的表达及其临床意义。 方法： 67例大肠腺癌、30例大肠腺瘤病例选自辽宁医学院附属第一医院病理科2010-2012年手术切除标本，30例对应癌旁黏膜组织（距癌组织边缘5 cm）作为对照。应用免疫组织化学方法检测大肠腺癌和腺瘤组织中XIAP与caspase-3蛋白的表达；应用Western blotting检测大肠腺癌及腺瘤组织中XIAP蛋白的表达，分析其与大肠腺癌临床病理参数的关系。 结果： XIAP蛋白在大肠腺癌组织中的阳性表达率 (71.6%) 明显高于腺瘤组织（46.7%），阳性率随组织分化程度的降低而明显增高（χ2=16.132，P<0.05）; caspase-3蛋白在大肠腺癌组织中的阳性表达率（18.0%）明显低于腺瘤组（43.3%），并随病理分化程度的降低而降低（χ2=7.743，P<005）。XIAP蛋白与caspase-3蛋白在大肠腺癌中的表达呈负相关（r=-0.396，P<005）。 结论： XIAP蛋白可能通过抑制caspase-3对大肠腺瘤转化成腺癌的演变起促进作用。

Objective: To explore the clinical significance of the expressions of XIAP（X-linked inhibitor of apoptosis protein) and caspase-3 in colorectal adenocarcinoma and adenoma. Methods: Sixty-seven cases with colorectal adenocarcinoma, 30 cases of colorectal adenoma cases selected from the Department of Pathology, First Affiliated Hospital of Liaoning Medical College from 2010 to 2012 with surgical resection, and 30 cases of corresponding adjacent mucosa (the distance from the edge of the cancerous tissue 5 cm) were used as a control. Immunohistochemistry was used to detect the expressions of XIAP and caspase-3 proteins in colorectal adenocarcinoma and adenoma tissues; Western blotting was used to detect the expression of XIAP in the colorectal adenocarcinoma and adenoma tissues; The relationship between the expression of XIAP and the clinical pathology parameters of colorectal adenocarcinoma was analyzed. Results: The positive rate of XIAP expression in the colorectal adenoma group (71.6%) was higher than that in colorectal adenocarcinoma (46.7%), and its expression rate was increasing with the decrease of the tissue differentiation degree (χ2=16.132, P<0.05); the positive rate of caspase-3 expression in the colorectal adenocarcinoma tissues (18.0%) was lower than that in the colorectal adenoma group (43.3%), and its expression rate was decreased with the decrease of the pathological differentiation degree (P<0.05). The expression of XIAP protein was in a negative correlation with that of caspase-3 (r=-0.396, P<0.05). Conclusion: The XIAP protein might play a significant role in promoting the progress from colorectal adenoma to colorectal adenocarcinoma by inhibiting caspase-3.