[目的]研究转化生长因子β(TGF-β)Ⅱ型受体(TGF-βRⅡ)及周期素D1(Cyclin D1)在大肠癌、大肠腺瘤中的表达,探讨其在大肠癌发病中的作用机制。[方法]应用免疫组织化学SABC法,即应用兔抗人TGF-βⅡ单抗和鼠抗人Cyclin D1单抗,对56例大肠癌、29例大肠腺瘤及56例相应癌旁正常组织进行免疫组织化学染色。[结果]TGF-βRⅡ表达主要位于细胞膜和细胞质中,其在大肠癌中的阳性表达率(44.64%)明显低于大肠腺瘤组织和正常组织(82.76%和96.43%)。Cyclin D1表达主要位于细胞核,其在大肠癌中的阳性表达率(89.29%)明显高于大肠腺瘤组织(41.38%),而正常大肠黏膜未见Cyclin D1强阳性表达。Cyclin D1过表达可明显降低TGF-βRⅡ的表达,二者呈明显的负相关。[结论]TGF-βRⅡ表达下降及Cyclin D1过表达可能在大肠癌发生过程中起重要作用。 [Objective] To investigate the expression of TGF-βRⅡ and Cyclin D1 in colorectal carcinoma and colorectal adenoma and to explore its role in the pathogenesis of colorectal cancer mechanism. [Methods] Immunohistochemical SABC method was used to immunize 56 cases of colorectal cancer, 29 cases of colorectal adenoma and 56 cases of corresponding normal tissues adjacent to normal tissue by using anti-human TGF-βⅡ monoclonal antibody and mouse anti-human Cyclin D1 monoclonal antibody Histochemical staining. [Results] The expression of TGF-βRⅡ was mainly located in the cell membrane and cytoplasm. The positive expression rate of TGF-βRⅡ in colorectal carcinoma was significantly lower than that in colorectal adenomas and normal tissues (44.7% vs 44.2%, 82.76% vs 96.43%, respectively). The expression of Cyclin D1 was mainly located in the nucleus. The positive expression rate of Cyclin D1 in colorectal carcinoma (89.29%) was significantly higher than that in colorectal adenomas (41.38%), while Cyclin D1 was not found in normal colorectal mucosa. Cyclin D1 overexpression significantly reduced the expression of TGF-βRⅡ, which showed a significant negative correlation. [Conclusion] Decreased expression of TGF-βRⅡ and overexpression of Cyclin D1 may play an important role in the carcinogenesis of colorectal cancer.