A case-cohort study of human herpesvirus 8 seropositivity and incident prostate cancer in Tobago

Seroprevalence of Herpes Simplex Virus Type 2 and Human Herpesvirus Type 8 among Prostate Cancer Patients Compared to Cancer-Free Men

Background: As one of the most prevalent cancers in men, prostate cancer is a condition with multiple causes. Viral infections have been identified as one of the major sources of elevated incidence of prostate cancer. Objectives: The purpose of this research was to assess the association of the risk of prostate cancer and its aggressiveness with seropositivity of herpes simplex virus 2 (HSV-2) and/or human herpesvirus 8 (HHV-8). Methods: Totally, 103 men with prostate cancer as cases and 81 healthy individuals as controls were included in this case-control analysis and provided a serum sample. The specific IgG antibodies against HSV-2 and HHV-8 were screened by enzyme-linked immunosorbent assay (ELISA). To determine the association between HSV-2, HHV-8, prostate-specific antigen (PSA) level, and demographic variables with incidence of prostate cancer, univariate and multivariate logistic regression models were applied. Results: The results of the univariate logistic regression model showed a statistically significant association between HSV-2 and HHV-8 seropositivity, PSA level, age, and smoking with prostate cancer incidence (P ≤ 0.20). The multivariate logistic regression model results after adjusting for the potential confounding variables showed a significant statistical association between the mean of PSA level [adjusted odds ratio (OR): 3.44; 95% CI: 2.15 - 5.51; P < 0.001) and incidence of prostate cancer. Moreover, the results of univariate and multivariate logistic regression model showed a significant statistical association between age [adjusted OR: 0.88; 95% confidence interval (CI): 0.81 - 0.95; P = 0.001] and HSV-2 and also significant statistical association was found between PSA (adjusted OR: 1.02; 95% CI: 1.005 - 1.03; P = 0.006) and HHV-8. Conclusions: Although the seroprevalence of HSV-2 and HHV-8 was higher in patients with prostate cancer than in the control group, it cannot be concluded that there is a significant association between the seropositivity of these viruses and prostate cancer incidence. However, the findings showed a significant statistical association between age and seropositivity of HSV-2 and also a significant statistical association between PSA levels and seropositivity of HHV-8.

Trichomonas vaginalis infection and prostate-specific antigen concentration: Insights into prostate involvement and prostate disease risk

BACKGROUND

The protist Trichomonas vaginalis causes a common, sexually transmitted infection and has been proposed to contribute to the development of chronic prostate conditions, including benign prostatic hyperplasia and prostate cancer. However, few studies have investigated the extent to which it involves the prostate in the current antimicrobial era. We addressed this question by investigating the relation between T. vaginalis antibody serostatus and serum prostate-specific antigen (PSA) concentration, a marker of prostate infection, inflammation, and/or cell damage, in young, male, US military members.

METHODS

We measured T. vaginalis serum IgG antibodies and serum total PSA concentration in a random sample of 732 young, male US active duty military members. Associations between T. vaginalis serostatus and PSA were investigated by linear regression.

RESULTS

Of the 732 participants, 341 (46.6%) had a low T. vaginalis seropositive score and 198 (27.0%) had a high score, with the remainder seronegative. No significant differences were observed in the distribution of PSA by T. vaginalis serostatus. However, slightly greater, nonsignificant differences were observed when men with high T. vaginalis seropositive scores were compared with seronegative men, and when higher PSA concentrations were examined (≥0.70 ng/mL). Specifically, 42.5% of men with high seropositive scores had a PSA concentration greater than or equal to 0.70 ng/mL compared with 33.2% of seronegative men (adjusted P = .125).

CONCLUSIONS

Overall, our findings do not provide strong support for prostate involvement during T. vaginalis infection, although our suggestive positive findings for higher PSA concentrations do not rule out this possibility entirely. These suggestive findings may be relevant for prostate condition development because higher early- to mid-life PSA concentrations have been found to predict greater prostate cancer risk later in life.

Sustained influence of infections on prostate-specific antigen concentration: An analysis of changes over 10 years of follow-up

BACKGROUND

To extend our previous observation of a short-term rise in prostate-specific antigen (PSA) concentration, a marker of prostate inflammation and cell damage, during and immediately following sexually transmitted and systemic infections, we examined the longer-term influence of these infections, both individually and cumulatively, on PSA over a mean of 10 years of follow-up in young active duty U.S. servicemen.

METHODS

We measured PSA in serum specimens collected in 1995-7 (baseline) and 2004-6 (follow-up) from 265 men diagnosed with chlamydia (CT), 72 with gonorrhea (GC), 37 with non-chlamydial, non-gonococcal urethritis (NCNGU), 58 with infectious mononucleosis (IM), 91 with other systemic or non-genitourinary infections such as varicella; and 125-258 men with no infectious disease diagnoses in their medical record during follow-up (controls). We examined the influence of these infections on PSA change between baseline and follow-up.

RESULTS

The proportion of men with any increase in PSA (>0 ng/mL) over the 10-year average follow-up was significantly higher in men with histories of sexually transmitted infections (CT, GC, and NCNGU; 67.7% vs 60.8%, P = 0.043), systemic infections (66.7% vs 54.4%, P = 0.047), or any infections (all cases combined; 68.5% vs 54.4%, P = 0.003) in their military medical record compared to controls.

CONCLUSIONS

While PSA has been previously shown to rise during acute infection, these findings demonstrate that PSA remains elevated over a longer period. Additionally, the overall infection burden, rather than solely genitourinary-specific infection burden, contributed to these long-term changes, possibly implying a role for the cumulative burden of infections in prostate cancer risk.

Social determinants of prostate cancer in the Caribbean: a systematic review and meta-analysis

BACKGROUND

Prostate cancer remains the leading cause of cancer deaths among Caribbean men. However, little data exists on the influence of social factors on prostate cancer in the Caribbean setting. This article supports the 2011 Rio Political Declaration on addressing health inequalities by presenting a systematic review of evidence on the role of social determinants on prostate cancer in Caribbean men. It aims to determine the distribution, by known social determinants of health, of the frequency and adverse outcomes of prostate cancer among Caribbean populations.

METHODS

Observational studies reporting an association between a social determinant and prostate cancer frequency and outcomes were sought in MEDLINE, EMBASE, SciELO, CINAHL, CUMED, LILACS, and IBECS databases. Fourteen social determinants and 7 prostate cancer endpoints were chosen, providing 98 possible relationship groups exploring the role of social determinants on prostate cancer. Observational studies with > 50 participants conducted in Caribbean territories between 2004 and 2016 were eligible. The review was conducted according to STROBE and PRISMA guidelines. Random-effects meta-analyses were performed.

RESULTS

From 843 potentially relevant citations, 13 articles from 9 studies were included. From these included studies, 24 relationships were reported looking at 11 distinct relationship groups, leaving 90 relationship groups (92% of all relationship groups) unexplored. Study heterogeneity and risk of bias restricted results to a narrative synthesis in most instances. Meta-analyses showed more diagnosed prostate cancer among men with less formal education (n = 2 studies, OR 1.60, 95%CI 1.18-2.19) and among men who were married (n = 3 studies, OR 1.54, 95%CI 1.22-1.95).

CONCLUSIONS

This review highlights limited evidence for a higher occurrence of diagnosed prostate cancer among Caribbean men with lower levels of education and among men who are married. The role of social determinants on prostate cancer among Caribbean men remains poorly understood. Improvements in study quantity and quality, and reduced variability in outcomes and reporting are needed. This report represents the current evidence, and provides a roadmap to future research priorities for a better understanding of Caribbean prostate cancer inequalities.

Elevated Serum PSA is Associated With Human Herpesvirus 8 Infection and Increased Circulating Cytokine Levels in Men From Tobago

BACKGROUND

Serum-prostate specific antigen (PSA) levels have been used for many years as a biomarker for prostate cancer. This usage is under scrutiny due to the fact that elevated PSA levels can be caused by other conditions such as benign prostatic hyperplasia and infections of or injury to the prostate. As a result, the identification of specific pathogens capable of increasing serum levels of PSA is important. A potential candidate responsible for elevated PSA is human herpesvirus 8 (HHV-8). We have reported previously that HHV-8 is capable of infecting and establishing a latent infection in the prostate. In this current study we test the hypothesis that HHV-8 infection is associated with elevated PSA levels. Circulating cytokine levels between men with elevated PSA and controls are also compared.

METHODS

HHV-8 serostatus was determined among men with elevated serum PSA (≥4 ng/ml; n = 168, no prostate cancer on biopsy) and age-matched controls (PSA <4 ng/ml; n = 234), Circulating cytokine levels were determined among a subset of each group (116 with elevated PSA and 85 controls).

RESULTS

Men with an elevated serum PSA were significantly more likely to be HHV-8 seropositive (42.9%) than the age-matched cancer-free men (22.2%; OR 2.51; 95%CI 1.48-4.29, P = 00001). Comparison of circulating cytokine levels between men with elevated serum PSA and controls indicated that elevated serum PSA is associated with a pro-inflammatory response with a mixed Th1/Th2 response while HHV-8 infection was associated with significantly higher levels of IL12p70, IL-10, and IL-13 indicating a Th2 immune response.

CONCLUSIONS

We found a significant association between HHV-8 infection and increased levels of serum PSA. In an age of patient-centered medicine, men with an elevated serum PSA should be considered for HHV-8 serology testing to determine if HHV-8 is responsible for the elevated PSA. Prostate 77: 617-624, 2017. © 2017 Wiley Periodicals, Inc.

Human herpesvirus 8 establishes a latent infection in prostates of Tobago men resulting in increased macrophage infiltration

BACKGROUND

The Caribbean island of Tobago, which is 97% African ancestry, has one of the highest rates of prostate cancer in the world. We have previously reported that human herpesvirus 8 (HHV-8) infection is significantly associated with prostate cancer in Tobago. In this study, we extend those results testing the hypothesis that HHV-8 seropositive Tobagonian men have a chronic HHV-8 infection in their prostates that is associated with increased inflammation.

METHODS

Prostate sections were screened by immunohistochemistry for the expression of HHV-8 proteins K8.1 and LANA-1 and for presence of B cells (CD20) and macrophages (CD68).

RESULTS

HHV-8 antigen expression representing lytic and latent infections was seen in 73.9% of prostates from HHV-8 seropositive subjects. Latent infections were seen predominantly in glandular epithelia whereas lytic gene expression was seen mainly in macrophages in prostate stroma. Macrophage infiltrates were significantly increased in sections expressing HHV-8 proteins.

CONCLUSION

HHV-8 establishes a chronic latent infection in the prostate, which is associated with an increased macrophage infiltrate.

Human herpesvirus 8 seroconversion in a population-based cohort of men in Tobago

Human herpesvirus 8 (HHV-8) is the causal agent of Kaposi's sarcoma (KS). In Tobago, KS is not common; however, HHV-8 seropositivity has been reported to be 39.9% in men with prostate cancer compared to <22.9% in healthier women and men. To understand HHV-8 transmission, we examined HHV-8 seroconversion and seroreversion, and risk factors for these changes in Tobago men. Serum specimens from a sub-cohort of Tobago Prostate Survey men, aged 40-81 years (n = 381/442), were collected at baseline and a subsequent visit between 3 and 9 years and tested for HHV-8 seropositivity using an immunofluorescence assay for antibodies against HHV-8 lytic antigens. Poisson distribution was used to calculate HHV-8 seroconversion and seroreversion rates and their 95% confidence intervals. Differences in baseline characteristics between HHV-seroconverters versus persistent HHV-8 seronegative men and HHV-8 seroreverters versus HHV-8 seropositive men were examined. HHV-8 seropositivity was 12.3% (N = 381) at baseline, with HHV-8 seropositivity significantly higher in increasing age groups, 40-49 (4.0%) to 70-81 (37.5%) years (P-value trend <0.0001). HHV-8 seroconversion and seroreversion rates were 0.23 per 100 person-years (95% C.I., 0.06-0.58) and 2.42 per 100 person-years (95% C.I., 0.89-5.26), respectively. There were significantly more HHV-8 seroconverters who reported "ever smoked cigarettes of >6 months" at baseline compared to HHV-8 persistent seronegative men (P-value = 0.03). Baseline characteristics of HHV-8 seroreverters did not differ from persistent seropositive men. Low HHV-8 seroconversion and seroreversion rates were found. Data suggest that HHV-8 transmission occurred at earlier ages, <40 years, in Tobago men.

Prospective study of human herpesvirus type 8 serostatus and prostate cancer risk in the placebo arm of the Prostate Cancer Prevention Trial

BACKGROUND

Human herpesvirus type 8 (HHV-8), a gamma herpesvirus associated with Kaposi's sarcoma, has been proposed as a candidate risk factor for prostate cancer (PCa) because of its detection in benign and malignant prostate specimens, and its relation with histologic prostatic inflammation. We investigated the possible relation between pre-diagnostic HHV-8 infection and PCa risk in a case-control study sampled from the placebo arm of the Prostate Cancer Prevention Trial.

METHODS

We defined cases as men with a confirmed diagnosis of PCa after visit 2 (n = 315) and controls as men not diagnosed with PCa during the trial who also had a negative end-of-study prostate biopsy (n = 315). We tested sera from visit 2 for IgG antibodies against HHV-8 using a monoclonal antibody-enhanced immunofluorescence assay against multiple lytic HHV-8 antigens.

RESULTS

The adjusted seroprevalence of HHV-8 infection was 11.6 % for cases and 11.0 % for controls (p = 0.81). No association was observed between HHV-8 seropositivity and PCa risk (OR 1.06, 95 % CI 0.65-1.76).

CONCLUSION

Our findings of a null association between HHV-8 seropositivity and PCa risk do not support an association between HHV-8 infection and PCa development, consistent with the general tendency of the epidemiologic literature to date.

Herpes simplex virus type 2 or human herpesvirus 8 infection and prostate cancer risk: A meta-analysis

Prostate cancer is the second most frequently diagnosed type of cancer and the sixth leading cause of cancer mortality among males worldwide. The aim of this study was to investigate the association between the infection by herpes simplex virus type 2 (HSV-2) or human herpesvirus 8 (HHV-8) and the risk of prostate cancer. A systematic literature search was performed using PubMed, Cochrane Library, Web of Science, Scopus, CNKI and CBM. The association of HSV-2 or HHV-8 infection with the risk of prostate cancer was separately assessed. Estimates of the odds ratio (OR) with 95% confidence interval (CI) were pooled by the fixed- or random-effects model. A total of 11 articles with 2,996 cases and 3,875 controls were included in this meta-analysis. HSV-2 infection was associated with increased prostate cancer risk (OR=1.209; 95% CI, 1.003-1.456). Results of the stratified analysis suggested that such an association existed among participants from North and South America (OR=1.226; 95% CI, 1.000-1.503). No significant correlation was observed in the HHV-8 group (OR=1.106; 95% CI, 0.765-1.598). Further investigations and large-sample studies are required to elucidate the possible mechanism underlying viral carcinogenesis and the association between herpes virus infection and the risk of prostate cancer.

Thirty years of research on infection and prostate cancer: no conclusive evidence for a link. A systematic review

BACKGROUND

The potential role of genitourinary infection in the etiology of prostate cancer (CaP) has been extensively investigated for 30 years. Two basic approaches have been used: tissue-based methods (polymerase chain reaction, immunohistochemistry, and in situ hybridization) and serologic assays (enzyme-linked immunosorbent assay, immunofluorescence, etc.). The objective of this review was to answer the question of whether infection of the male genitourinary tract may have a role in the etiology of CaP.

MATERIALS AND METHODS

We have carried out a systematic review of the evidence that was published in the MEDLINE/PubMed database until December 2011. The search terms included "prostate cancer," "infection," and the explicit names of the various infectious agents. Additional studies were identified using a reference search. A total of 74 papers were included in the review, which cover the following infectious agents: human papillomavirus, cytomegalovirus, herpes simplex virus, Epstein-Barr virus, human herpesvirus, BK virus, JC virus, chlamydia, mycoplasma, ureaplasma, trichomonas, neisseria, treponema, Propionibacterium acnes, xenotropic murine leukemia virus-related virus and Candida albicans.

RESULTS

Despite the variable study designs and methodological approaches that were used, most of the pathogens that were studied were unlikely to be directly involved in prostate carcinogenesis.

CONCLUSIONS

The role of infection in the etiology of CaP has yet to be determined despite 30 years of research efforts. A discovery of an infectious agent that is associated with CaP would be of great medical importance; however, such a link would have to be firmly established before impacting on patient care.