Am J Epidemiol. 2013 Sep 15;178(6):885-7. doi: 10.1093/aje/kwt149. Epub 2013 Jul 30.
Anal cancer is common among people infected with human immunodeficiency virus (HIV). This cancer is caused by human papillomavirus, and immunosuppression likely contributes to its development. In this issue of the Journal, Bertisch et al. (Am J Epidemiol. 2013;178(6):877-884) present the results of a case-control study of anal cancer among HIV-infected people in Switzerland. They demonstrate that anal cancer risk is increased in association with a low CD4+ cell count (a clinical measurement of immune status). In particular, HIV-induced immunosuppression was most severe among cases approximately 6-7 years prior to the diagnosis of anal cancer. A plausible biological interpretation is that immunosuppression is important at an early stage of the development of anal cancer, but that the neoplastic process becomes irreversible over time with persistent human papillomavirus infection and genetic damage. With current efforts to provide earlier combination antiretroviral therapy to HIV-infected people, anal cancer incidence may start to decline. Bertisch et al. also demonstrate a strong association between serum antibodies against the human papillomavirus type 16 protein E6 and anal cancer risk, highlighting the role of this viral oncoprotein in carcinogenesis. Additional biomarkers could help refine clinical approaches to anal cancer screening and prevention for the HIV-infected population.
肛门癌常见于感染人类免疫缺陷病毒 (HIV) 的人群中。这种癌症是由人乳头瘤病毒引起的，免疫抑制可能促成了其发展。在本期《美国流行病学杂志》中，Bertisch 等人（Am J Epidemiol. 2013;178(6):877-884）报告了一项针对瑞士 HIV 感染者肛门癌的病例对照研究结果。他们表明，肛门癌的风险与低 CD4+细胞计数（一种免疫状态的临床测量）相关而增加。特别是，在肛门癌诊断前约 6-7 年，HIV 诱导的免疫抑制在病例中最为严重。一个合理的生物学解释是，免疫抑制在肛门癌发展的早期阶段很重要，但随着持续的人乳头瘤病毒感染和遗传损伤，肿瘤过程会随着时间的推移而变得不可逆转。随着目前为 HIV 感染者提供更早的联合抗逆转录病毒治疗的努力，肛门癌的发病率可能开始下降。Bertisch 等人还表明，血清中针对人乳头瘤病毒 16 型蛋白 E6 的抗体与肛门癌风险之间存在强烈关联，突出了这种病毒致癌蛋白在致癌作用中的作用。其他生物标志物可能有助于完善针对 HIV 感染者的肛门癌筛查和预防的临床方法。
