结直肠癌组织HPV16 E7 DNA及蛋白表达的研究

目的　分析不同部位、分期的结直肠癌及正常黏膜组织中人乳头状瘤病毒(human papilloma virus,HPV)16型E7的表达状况。方法　应用PCR及免疫组化方法检测82例手术切除的结直肠癌新鲜标本及距肿瘤近端10 cm以远的正常黏膜组织中HPV16 E7 DNA及蛋白的表达。结果　结直肠癌组织HPV16 E7 DNA表达阳性率为51.22%(42/82),明显高于正常黏膜组织的4.88%(4/82),P<0.01; 直肠癌组织中HPV16 E7 DNA表达阳性率为64.10%(25/39),明显高于升结肠癌的18. 18%(2/11), P<0. 05; HPV16 E7 DNA表达阳性率与Dukes分期有关(P<0.01),与癌组织分化程度无关。免疫组化染色显示,HPV16 E7蛋白主要为细胞核表达,胞浆也可见少量表达,进一步确认了HPV16的感染,且HPV16 E7蛋白与HPV16 E7 基因的表达具有相关性,免疫组化敏感性较PCR方法为低。结论　结直肠癌组织HPV16 E7 DNA及蛋白的表达阳性率明显高于正常黏膜组织,提示部分结直肠癌存在HPV16感染。癌灶部位距肛门越近,感染率越高; Dukes分期越晚感染率越高。

Detection of Human Papilloma Virus 16 E7 DNA and Protein in Patients with Colorectal Carcinoma

Objective To detect the expression of human papilloma virus(HPV) 16 E7 was detected in colorectal adenocarcinoma tissue and normal mucosa. Methods Eighty-two patients with primary colorectal adenocarcinoma were selected in this study. The samples were taken from the tumor and the adjacent normal mucosa (10 cm away from the tumor) in each patient. Polymerase chain reaction (PCR) and immunohistochemistry were used to detect HPV16 E7 DNA and protein respectively. Results HPV16 E7 DNA expression was significantly higher in colorectal carcinoma (51.22%,42/82) than that in adjacent normal mucosa (4.88%,4/82), P <0.01. A correlation was found between HPV16 E7 DNA expression and tumor location ( P <0.05),18.18% in the ascending colon carcinoma and 64.10% in the rectal carcinoma. HPV16 E7 DNA expression was also associated with Dukes stage( P < 0.01), but was not correlated with cancer differentiation. HPV16 E7 protein expression was mainly dectected in the nuclei of tumor cells with immunohistochemistry. There was a correlation between the expression of HPV16 E7 protein and HPV16 E7 gene. PCR had a higher sensitivity than immunohistochemistry. Conclusion HPV16 infection rate is much higher in the colorectal carcinoma than that in the adjacent normal mucosa, which indicates that HPV16 infection exists in some colorectal carcinomas. The high infection rate of HPV16 E7 is associated with advanced Dukes stage and proximity to anus.