p16基因甲基化及P16、Cyclin D1、pRb与皮肤鳞状细胞癌相关性研究

A study on the relationship between the primary cutaneous squamous cell carcinomaand the methylation of p16 gene,P16,Cyclin D1 and pRb

目的探讨P16、Cyclin D1和pRb蛋白在皮肤鳞状细胞癌(简称皮肤鳞癌)中的表达及他们的相互关系和意义；研究p16基因甲基化是否与原发性皮肤鳞癌的发生有关。方法采用PCR为基础的限制性内切酶甲基化法及免疫组化S-P法检测40例原发性皮肤鳞癌组织中p16基因甲基化状态及P16、Cyclin D1和pRb蛋白的表达,并以10例正常皮肤组织作对照。结果皮肤鳞癌组织P16蛋白、Cyclin D1阳性表达率分别为37．5％和57．5％；P16蛋白表达与Cyclin D1的表达呈显著负相关(r=-0．3162,P=0．008)。皮肤鳞癌中P16蛋白和pRb表达呈显著负相关(r=-0．4007,P<0．05)。p16基因的甲基化阳性率为42．5％。2级皮肤鳞癌组织中P16蛋白及p16基因甲基化阳性表达率比1级鳞癌组织显著增高(P<0．05),而Cyclin D1和pRb阳性率表达则显著降低(P<0．05)。在有淋巴结转移组中P16蛋白及p16基因甲基化阳性率与无淋巴结转移组相比显著降低(P<0．05),而Cyclin D1和pRb阳性率则显著增加(P<0．05)。结论在原发性皮肤鳞状细胞癌中存在P16蛋白低表达、CyclinD1高表达的异常表达现象,两者的表达相互抑制,呈显著负相关；P16蛋白和pRb蛋白的表达呈负相关；p16基因甲基化与皮肤鳞癌病理分级、淋巴结转移之间有显著关系。提示p16基因甲基化在皮肤鳞癌的发生发展过程中起重要作用。

Objective To investigate the expression and its significance of P16, Cyclin D1 and pRb in human outrageous squamous cell carcinoma （CSCC） and the relationship between the throe proteins, and to investigate the rolationship between the methylation of p16 gene and the development of the CSCC. Methods PCR - based methylation assay and S- P immunohistochemistry methods were applied to determine the methylation of p16 gene and the expression of P16, Cycliu I）1 and pRb in 40 cases of primary CSCC and 10 normal skin tissue control samples. Results The expression rates of Cyclin D1 and pRb protein were 57.5% and 52.5% respectively in the 40 cases of primary CSCC. Inverse conrelation was found between P16 and Cyclin DI, and between P16 and pRb as well （P 〈 0.05）. The methylation rate of p16 gene was 42.5%. The positive expression rates of P16 and p16 gene methylation were significantly decreased in CSCC grade 2, as compared with that in CSCC grade I （ P 〈 0.05）. Conversely, the former were lower, while the latter were higher, in the CSCC with lymphatic metastasis than in the CSCC without （P 〈 0.05）. Conclusion The low expression of P16 protein and the methylation of p16 gene are significantly involved in the development of CSCC.