口腔鳞癌和癌前病变中微小染色体维持蛋白7和细胞分裂周期蛋白6的表达研究

Expression of minichromosome maintenance protein 7 and cell division cycle protein6 and its significance in oral squamous cell carcinoma and precancerous lesion

目的探讨微小染色体维持蛋白7(Mcm7)和细胞分裂周期蛋白6(Cdc6)在口腔鳞癌(OSCC)和癌前病变中的表达及临床意义。方法采用反转录聚合酶链反应(RT-PCR)及免疫组化方法分别检测47例冰冻标本、98例石蜡标本中Mcm7和Cdc6的mRNA及蛋白表达水平,分析其表达与病理分级、临床分期及淋巴结转移等因素之间的相关性。结果 RT-PCR结果显示Mcm7 mRNA在口腔正常黏膜、癌前病变以及OSCC组织中均有阳性表达,各组之间相对表达量差异有统计学意义(P<0.01)。Cdc6 mRNA在正常黏膜中鲜有表达,癌前病变组与OSCC组均有阳性表达,各组之间相对表达量差异亦有统计学意义(P<0.01)。免疫组化结果显示Mcm7蛋白在口腔正常黏膜、癌前病变以及OSCC组织中均有阳性表达,其阳性标记指数分别为3.6%、22.3%和45.9%,各组之间阳性标记指数差异有统计学意义(P<0.01)。OSCC组Mcm7蛋白表达阳性指数高于癌前病变组(P<0.01)。Cdc6蛋白在以上标本中的阳性表达总体较Mcm7低,在正常口腔黏膜中鲜有表达,癌前病变以及OSCC组织中均有阳性表达。各组之间阳性标记指数差异有统计学意义(P<0.01)。Mcm7和Cdc6在有淋巴结转移组其阳性标记指数高于无转移组(P<0.01)。结论 Mcm7和Cdc6的高表达与口腔癌发生及转移有相关性。检测OSCC组织中Mcm7和Cdc6的表达有望成为其早期诊断与判断预后的分子指标之一。

Objective To evaluate the expression of minichromosome maintenance protein7（Mcm7） and cell division cycle protein 6（Cdc6） and to determine its significance in oral squamous cell carcinoma（OSCC） and precancerous lesion.Methods RT-PCR and immunohistochemistry analysis were performed on 47 frozen samples and 98 paraffin-embedded samples to evaluate mRNA and protein expressions of Mcm7 and Cdc6.Results RT-PCR results indicated positive expressions of Mcm7 mRNA in normal oral mucosa,precancerous lesions,and squamous cell carcinomas and significant differences were found among different groups（P 0.01）.Cdc6 mRNA had low expression in normal oral mucosa and was highly expressed in precancerous lesions and squamous cell carcinoma,with significant differences delete among all groups（P 0.01）.Immunohistochemistry analysis results indicated positive protein expression of Mcm7 in the normal oral mucosa,precancerous lesions,and squamous cell carcinomas,with a labelling index of 3.6%,22.3% and 45.9% respectively.Significant differences were found among all groups（P 0.01）.Mcm7 positive protein expression was significantly higher in the squamous cell carcinoma group than that of the precancerous lesion group（P 0.01）.Cdc6 positive protein expression was lower than Mcm7 expression in all samples,with low expressions observed in normal oral mucosa,and high expressions in precancerous lesions and squamous cell carcinomas.Labelling index values among groups were statistically significant（P 0.01）.Mcm7 and Cdc6 expressions in the lymph node metastasis group were significantly higher than those of the non-metastasis group（P 0.01）.Conclusions The expression of Mcm7 and Cdc6 is positively correlated to OSCC occurrence and lymph node metastasis.Detection of the expression of Mcm7 and Cdc6 may be used for early diagnosis and prognostic judgment of oral squamous cell carcinoma.