Plasma antibodies against Chlamydia trachomatis, human papillomavirus and human herpesvirus type 8 infection in relation to prostate cancer: A prospective study.

B209

Purpose: Traditionally, case-control studies of sexually transmitted infections (STIs) and prostate cancer have focused on gonorrhea and syphilis, with overall positive associations. More recently, researchers have begun to investigate additional STIs in relation to prostate cancer, reflecting the expanding number of recognized STI pathogens over time. These additional STIs include Chlamydia trachomatis, human papillomavirus (HPV) and human herpesvirus type 8 (HHV-8) infection. C. trachomatis is a putative, candidate infection because it is often asymptomatic in men, and may thus persist longer in the male genitourinary tract, and possibly ascend to the prostate, where it has been observed to infect prostate epithelial cells and elicit an intraprostatic inflammatory immune response. HPV and HHV-8 have both been associated with other cancers, and have both been detected (with some debate) in prostate tissue. We investigated each of these infections in relation to incident prostate cancer in a nested case-control study within the Health Professionals Follow-up Study. Materials and methods: Prostate cancer cases were defined as men diagnosed with prostate cancer between the date of blood draw (1993-5) and 2000 (n = 691). Controls were defined as men free of prostate cancer and alive at the time of case diagnosis who had had at least one prostate specific antigen test by the time of case diagnosis. One control was individually matched to each case by age; year, time of day and season of blood draw; and PSA screening history prior to blood draw (n = 691). C. trachomatis and HPV-16, -18 and -33 antibody serostatus were assessed by enzyme-based immunoassays, and HHV-8 antibody serostatus was assessed by an immunofluorescence assay. Results: No associations were observed between C. trachomatis (OR=1.13, 95% CI: 0.65-1.96), HPV-16 (OR=0.83, 95% CI: 0.57-1.23), HPV-18 (OR=1.04, 95% CI: 0.66-1.64), HPV-33 (OR=1.14, 95% CI: 0.76-1.72) and any HPV (HPV-16, -18 or -33) antibody seropositivity (OR=0.92, 95% CI: 0.69-1.22) and prostate cancer. An inverse association was observed between HHV-8 antibody seropositivity and prostate cancer (OR=0.70, 95% CI: 0.52-0.95). Conclusions: In this large population of American male health professionals, no associations were observed between C. trachomatis and HPV-16, -18 and -33 antibody seropositivity and prostate cancer, whereas an inverse association was observed between HHV-8 antibody seropositivity and prostate cancer. As this study is the first, to our knowledge, to observe such an inverse association, similar additional studies are warranted before conclusions can be made.