APC、β-catenin及c-myc在大肠腺瘤-癌组织序列中的表达及其意义

Expression and Clinical Significance of APC β-catenin and c-myc in Colorectal Adenoma-adenocarcinoma Sequence

目的探讨大肠腺瘤性息肉病基因(adenomatous polysis coil,APC)、β-环形蛋白(β-catenin)及原癌基因蛋白c-myc的表达在大肠肿瘤发生发展中的作用及其与临床病理参数之间的关系。方法应用免疫组织化学SP法检测APC、β-catenin及c-myc在大肠正常黏膜、大肠腺瘤和大肠腺癌组织中的表达。结果①正常黏膜、大肠腺瘤和大肠腺癌中APC蛋白的表达率为97.3%、25.0%、24.6%。腺瘤与腺癌组均低于正常黏膜组(P<0.01),腺瘤与腺癌组差异不显著(P>0.05)。②β-catenin在正常黏膜组为胞膜表达,腺瘤与腺癌组呈胞质/核异位表达,异位表达率为10.8%、75.0%、98.2%,3组之间有显著性差异(P<0.01)。③正常黏膜、大肠腺瘤和大肠腺癌中c-myc的表达率为10.8%、40.6%、70.2%。3组之间有显著性差异(P<0.01)。④大肠腺癌中β-catenin蛋白的异常表达随着肿瘤大小、组织学分级、Dukes分期的改变呈逐渐增高趋势,有淋巴结转移者β-catenin蛋白阳性表达率(100.0%)高于无淋巴结转移者(96.4%),但无显著性差异(P>0.05)。结论APC的失表达、β-catenin的异常表达及c-myc的过表达与大肠肿瘤的发生发展有关,β-catenin的异常表达可能与大肠腺癌的恶性行为有关。

Objective To investigate the expression of APC,β-catenin and c-myc in the carcinogenesis and progression of colorectal carcinomas and their relationship with clinical pathological parameters. Methods Tissues from the normal colorectal mucosa,adenoma and adenocarcinoma were evaluated to determine the expression of APC,β-catenin and c-myc by immunohistochemical SP method. Results ①APC was expressed in 97.3% of the normal colorectal mucosa,25.0% of the adenoma and 24, 6% of the adenocarcinoma. APC expression was significantly lower in both adenoma and adenocarcinoma than that in normal mucosa（ P 〈 0.01 ） ,whereas the difference between adenoma and adenocarcinoma in the expression of APC was not significantly different（ P 〉0.05 ）. ②β-catenin expression was detected on the cell membrane in normal colorectal mucosa. In adenoma and adenocarcinoma, β-catenin was expressed in the cytoplasm and nucleus. The ectopic expression rates of β-catenin were 10, 8% ,75. 0% and 98.2%. The difference was statistically different（ P 〈0.01 ）. ③c-myc was expressed in 10.8% of the normal mucosa, 40.6% of the adenoma and 70.2% of the adenoearcinoma. There were significant differences among these three groups （P 〈 0. 01 ）. ④In colorectal adenocarcinoma, the ectopic expression of the β-catenin was positively correlated with the tumor volume, the pathological grade and the clinical stage. The expression of β-catenin was higher in patients with nodal metastasis （ 100.0% ） than those without nodal involvement （96.4%）, but there was no significantly difference （ P 〉 0.05 ）. Conclusion The deletion of APC,the ectopic expression of β-catenin and the overexpression of c-myc may be involved in the carcinogenesis and progression of coloreetal carcinoma. The ectopic expression of β-catenin may be related to the malignant biological behavior of colorectal adenocarcinoma.