INFECTIOUS ETIOLOGY TESTICULAR CANCER

睾丸癌发病率增加的趋势不太可能用隐睾症等已知的风险因素来解释。根据睾丸癌与其他病毒相关恶性肿瘤的年龄特异性发病模式之间的相似性，提出了睾丸癌的感染性病因学。只有少数流行病学研究评估了这一假设，但集体结果表明，暴露于EBV和CMV可能与睾丸癌的风险。进一步的间接证据来自表明免疫功能低下的男性风险增加的研究，以及表明睾丸癌与性传播疾病史之间关系的研究。关于性传播感染因子在睾丸癌病因学中的作用的直接流行病学证据是有限的，尽管具有启发性。使用前瞻性收集的血清，我们建议评估一方面对HSV-2、HPV-16和15、HHV-8和沙眼衣原体的抗体应答与另一方面睾丸癌发生之间的关联。作为第二个目标，我们将研究这些药物感染与睾丸癌之间的关联是否会因年龄而改变。该研究是一项病例对照研究，嵌套在一个明确定义的男性队列中，这些男性捐献血液样本作为挪威JANUS项目的一部分。JANUS项目由挪威癌症协会赞助，成立于1973年，目的是前瞻性收集血清，用于癌症发展和心血管疾病的流行病学研究。截至1993年10月，JANUS血清库中有来自293，692人的424，938份血清样本，其中没有一人在采血时患有癌症。JANUS血清库的所有献血者每年都通过唯一的个人识别号码与挪威癌症登记处联系。本分析的合格病例是1993年癌症登记处列出的诊断为侵袭性睾丸癌的男性献血者。对于每种情况，从JANUS血清库中随机选择三名献血者作为对照，这些献血者在样本采集时的年龄和年份分别匹配。共确定了88例病例患者和262例匹配对照，并将纳入拟定分析。血清抗HSV-2、HPV、HHV-8和C.将使用酶联免疫吸附和免疫荧光测定法测定沙眼。根据整个研究人群的分布，将个体抗体滴度值分布到四分位数中。考虑到个体匹配，将通过条件logistic回归对数据进行建模。JANUS队列提供了一个独特的机会来研究感染因子与睾丸癌风险的关系。据我们所知，这是第一项使用诊断前收集的血清评估睾丸癌病毒来源的研究。

The trend of increasing testicular cancer incidence is unlikely to be explained by known risk factors such as cryptorchidism. An infectious etiology of testicular cancer has been proposed, based on similarities between the age-specific incidence pattern of testicular cancer and that of other virus-associated malignancies. Only a small number of epidemiologic studies have evaluated this hypothesis, but collective results suggest that exposure to EBV and CMV may relate to testicular cancer risk. Further indirect evidence comes from studies showing increased risk among immunocompromised men, as well as from studies indicating a relation between testicular cancer and history of sexually transmitted diseases. Direct epidemiologic evidence regarding the role of sexually transmitted infectious agents in testicular cancer etiology is limited although suggestive. Using serum collected prospectively, we propose to evaluate the association between antibody response to HSV-2, HPV-16 and 15, HHV-8 and Chlamydia trachomatis on the one hand and the occurrence of testicular cancer on the other. As a secondary aim, we will examine whether the associations between infection with any of these agents and testicular cancer are modified by age. The proposed study is a case-control study nested in a well-defined cohort of men who donated blood samples as part of the JANUS project in Norway. The JANUS project, sponsored by the Norwegian Cancer Society, was established in 1973 for the purpose of prospectively collecting serum to be used in epidemiologic studies of cancer development and cardiovascular disease. As of October 1993, the JANUS serum bank contained 424,938 serum samples from 293,692 individuals, none of whom had cancer at the time of blood sampling. All blood donors to the JANUS serum bank are annually linked, through a unique, individual identification number, with the Cancer Registry of Norway. Eligible cases for the present analysis are male blood donors listed in the Cancer Registry through 1993 with a diagnosis of invasive testicular cancer. For each case, three blood donors, individually matched by age and year at sample collection, have been randomly selected from the JANUS serum bank as controls. A total of 88 case patients and 262 matched controls have been identified and will be included in the proposed analysis. Serum antibody titers against HSV-2, HPV, HHV-8 and C. trachomatis will be determined using enzyme-linked immunosorbent and immunofluorescence assays. Individual antibody titer values will be distributed into quartiles based on the distribution of the entire study population. The data will be modeled through conditional logistic regression, taking into account the individual matching. The JANUS cohort provides a unique opportunity to study infectious agents in relation to testicular cancer risk. To our knowledge, this is the first study to evaluate the viral origin of testicular cancer using serum collected prior to diagnosis.