大肠癌组织中p27蛋白表达与微卫星不稳定性的关系

Relationship Between the Expression of p27 Protein and Microsatellite Instability in Colorectal Carcinomas

目的探讨大肠癌组织中p27蛋白表达与微卫星不稳定(MSI)的关系。方法采用免疫组化、PCRSSCP法对53例散发性大肠癌分别进行p27蛋白表达水平和D18S34,TGFβRⅡ,APC(1),TCF2,p53(1)及Rb6个碱基序列位点的检测。结果53例大肠癌中25例存在微卫星不稳定,总阳性率为47.2%,其中23例存在2个以上位点的MSI,呈复制误差阳性(RER阳性),占43.4%。RER+者p27高表达率(82.6%)显著高于RER阴性者(43.3%),2组比较有非常显著性差异(P<0.01)。结论大肠癌MSI的发生可能对p27蛋白的表达有一定的上调作用。p27等一些细胞周期负调控因子在RER阳性大肠癌中的表达水平相对上调,可能是其细胞增殖活性较低、生物学行为较好的原因。

Objective To explore the relationship between the expression of p27 protein and microsatellite instability in colorectal carcinomas.Methods The expression of p27 protein was detected by immunohistochemical staining,and MSI at six microsatellite loci(D18S34,TGF-βRⅡ,APC(1),TCF-2,p53(1),and Rb) were examined by PCR-SSCP in 53 cases of sporadic colorectal carcinomas.Results The overall positive rate of MSI in CRC were 47.2%(25/53).23 case(23/53,43.4%) have MSI at 2 or more than 2 loci which showed DNA replication error(RER)-positive.The expression rate of p27 protein was significantly higher in RER-positive CRC than in RER-negative CRC(82.6% v.s.43.3%,P<0.01).Conclusion MSI in CRC may play an important role in the upregulation of the expression of P27 protein.In RER+ tumors,the expression of negative cell cycle regulators such as protein p27,are relatively upregulate,resulting in a low proliferating activity and a better biological behavior.