粘蛋白和上皮钙粘附蛋白在结直肠肿瘤组织中的表达及其意义

背景与目的:粘蛋白(mucin,MUC)是大分子量的糖蛋白,对上皮起润滑和保护作用.上皮钙粘附蛋白(E-cadherin,E-cad)可维持上皮的极性和完整性.MUC、E-cad异常表达与肿瘤的发生有关.本研究目的是探讨MUC1、MUC2、MUCSAC和E-cad在正常结直肠粘膜、结直肠腺瘤及结直肠腺癌组织中的表达及其与临床各个病理因素之间的关系,并且研究MUC1、MUC2、MUC5AC分别与E-cad表达之间的相关性.方法:应用免疫组织化学方法对正常结直肠粘膜、结直肠腺瘤及结直肠腺癌组织各150例进行MUC1、MUC2、MUC5AC和E-cad检测,并进行Kaplan-Meier生存分析.采用Spearman等级相关分析MUC1、MUC2、MUC5AC分别与E-cad之间的相关性.结果:在结直肠正常粘膜、腺瘤、腺癌中MUC1阳性率分别为0.07%、12.7%、45.3%; MUC2为100%、90.0%、52.6%;MUC5AC为8.7%、30.7%、44.0%;E-cad为98.7%、82.0%、54.0%.在结直肠腺癌中,MUC1、MUC2的表达与肿瘤的分化程度、浸润深度、淋巴结转移、Duke's分期有关(P＜0.05);MUC5AC的表达与分化程度、浸润深度有关(P＜0.01);E-cad的表达与分化程度有关(P＜0.01).Kaplan-Meier生存曲线及10g-rank显著性检验发现,MUC1阴性组及MUC2、E-cad阳性表达组5年生存率明显增高(P＜0.05).通过Spearman等级相关分析表明,在结直腺癌中MUC1与E-cad呈负相关(r=-0.234,P=0.004);MUC2、MUC5AC分别与E-cad呈正相关(r=0.170,P=0.038;r=0.198,P=0.015).结论:在结直肠腺癌中.MUC与E-cad具有明显相关性;MUC1、MUC5AC的上调表达,MUC2、E-ead的下调表达与结直肠肿瘤的发生有关,并在一定程度上与预后有关.

Expression and clinical significance of Mucin and E-cadherin in colorectal tumors

BACKGROUND & OBJECTIVE: Mucin (MUC), a glycoprotein with high molecular weight, can lubricate and protect the epithelium. E-cadherin (E-cad) is helpful in keeping the polarity and integrity of the epithelium. The abnormal expression of Mucin and E-cad is involved in the genesis of many tumors. This study was to investigate the expression of MUC1, MUC2, MUC5AC and E-cad in different colorectal tumor tissues, and explore their correlations to clinicopathologic features of colorectal cancer and the correlations of MUC1, MUC2, and MUC5AC expression to E-cad expression. METHODS: The expression of MUC1, MUC2, MUC5AC and E-cad in 150 specimens of normal colorectal mucosa, 150 specimens of colorectal adenoma and 150 specimens of colorectal adenocarcinoma was detected by immunohistochemistry. Patients' survival was analyzed by Kaplan-Meier method. The correlations of MUC1, MUC2, and MUC5AC expression to E-cad expression were analyzed by spearman's rank correlation. RESULTS: The positive rates of MUC1 were 0.07% in normal colorectal mucosa, 12.7% in colorectal adenoma, and 45.3% in colorectal adenocarcinoma. Those of MUC2 were 100%, 90.0% and 52.6%, respectively. Those of MUC5AC were 8.7%, 30.7% and 44.0%, respectively. Those of E-cad were 98.7%, 82.0% and 54.0%, respectively. In colorectal adenocarcinoma, the expression of MUC1 and MUC2 was correlated to tumor differentiation, invasion, lymph node metastasis and Dukes' stage (P<0.05); the expression of MUC5AC was correlated to tumor differentiation and invasion (P<0.01); the expression of E-cad was correlated to tumor differentiation (P<0.01). The 5-year survival rate was significantly higher in MUC1-negative group, MUC2-positive group and E-cadherin-positive group than in their counterparts (P<0.05). In colorectal adenocarcinoma, MUC1 expression was negatively correlated to E-cad expression (r=-0.234, P=0.004), MUC2 and MUC5AC expression were positively correlated to E-cad expression (r=0.170, P=0.038; r=0.198, P=0.015). CONCLUSIONS: In colorectal adenocarcinoma, MUC expression is obviously correlated to E-cad expression. The up-regulation of MUC1 and MUC5AC expression and the down-regulation of MUC2 and E-cad expression may be involved in the genesis of colorectal tumors and reflect the prognosis to a certain extent.