Sexually transmissible infections and prostate cancer risk

Highly sensitive deep panel sequencing of 27 HPV genotypes in prostate cancer biopsies results in very low detection rates and indicates that HPV is not a major etiological driver of this malignancy

BACKGROUND

Human papillomavirus (HPV) has been proposed to contribute to the carcinogenesis of prostate cancer. However, previous studies have yielded conflicting results. This study aims to add useful information to the ongoing discussion concerning the association between HPV infection and prostate cancer.

METHODS

We used two high-throughput next-generation sequencing (NGS) approaches to detect HPV RNA in malignant and adjacent normal (AN) prostate tissue (cohorts 1 and 2) and HPV DNA from carcinogenic and probably/possibly carcinogenic-classified HPV types (cohort 3) in malignant prostate, AN prostate, and benign prostatic hyperplasia (BPH) tissues.

RESULTS

In total, 0% (cohort 1: 0/83, cohort 2: 0/16) of the malignant prostate tissue samples and 0% (cohort 1: 0/23, cohort 2: 0/8) of the AN prostate tissue samples were positive for HPV RNA. A total of 8.3% (1/12) of the BPH samples, 0% (0/28) of the AN samples, and 0.8% (1/132) of the malignant prostate samples were positive for HPV16 DNA. However, the normalized read count of the HPV16-positive malignant sample was close to the cut-off. In addition, no other carcinogenic-classified HPV types were detected in any of the BPH, AN, or malignant prostate tissue samples.

CONCLUSION

Our study does not support HPV infection as a major contributor to the etiology of prostate cancer.

Can the Epstein-Barr Virus Play a Role in the Development of Prostate Cancer?

Prostate cancer (PCa) is the fourth most frequently diagnosed cancer worldwide, accounting for 7.3% of all cancers. PCa mortality is the fifth most common cause of cancer death. Despite well-known factors influencing the development of PCa, such as age, race/ethnicity and family history, many researchers have raised the possibility of persistent infections with oncogenic viruses. Therefore, we aimed to assess the frequency of Epstein-Barr virus (EBV) DNA in tissue collected from PCa patients. Next, the frequency and the level of Epstein-Barr virus capsid antigen (EBVCA) and Epstein-Barr nuclear antigen 1 (EBNA1) antibodies in both IgA and IgG classes were measured. The antibody titer was also analyzed depending on the risk group, Gleason score (GS) and tumor, node, metastasis (TNM) classification. Serum samples were analyzed using the Microblot-Array EBV IgM, IgA and IgG test kits. The study group consisted of 115 patients diagnosed and histopathologically confirmed with PCa. In 49% of patients included in the study, EBV DNA was detected in the tumor tissue. The studies showed both higher seroprevalence and higher antibody titers in patients with EBV-positive PCa compared to patients with EBV-negative PCa. We also observed a dependence of antibody titer on pathological features, such as GS, risk group and T stage.

Sexually and non-sexually transmitted infections and the risk of prostate cancer: Results from the EPICAP study

INTRODUCTION

Prostate cancer (PCa) is by far the most common type of cancer among men in western countries. However, relatively little is known about its etiology despite the high morbidity and mortality. It has been suggested that chronic inflammation may be involved in prostate carcinogenesis. We investigated the role of sexually and non-sexually transmitted infections in prostate cancer risk with a specific interest in the aggressive types.

METHODS

We used data from epidemiological study of prostate cancer (EPICAP), a population-based case-control study. A total of 819 incident cases and 879 controls were interviewed face-to-face using a standardized questionnaire gathering information on known or suspected risk factors of prostate cancer and personal history of specific sexually and non-sexually transmitted infections: gonorrhea, syphilis, trichomonas, herpes, mononucleosis, Epstein-Barr virus, varicella-zoster, and dengue. Odds ratios (OR) and their 95% confidence interval were estimated using multivariate unconditional logistic regression.

RESULTS

There was no significant association between gonorrhea (OR: 0.90, 95% CI: 0.61-1.33), trichomonas (OR: 0.74, 95% CI: 0.27-2.07), genital herpes (OR: 0.69, 95% CI: 0.38-1.27), and the risk of prostate cancer. No association emerged for overall sexually transmitted bacterial and viral infections (OR 1.05, 95% CI: 0.86-1.29) and overall non-sexually transmitted viral infections (OR 1.11, 95% CI: 0.90-1.35) and the risk of prostate cancer.

CONCLUSION

Our results showed that sexually or non-sexually transmitted infections, either bacterial or viral, were not associated to prostate cancer. Therefore, further investigation is needed to help advance our understanding of the role of chronic inflammation in the etiology of prostate cancer, with a particular focus on its most aggressive types.

No Association of Trichomonas vaginalis Seropositivity with Advanced Prostate Cancer Risk in the Multiethnic Cohort: A Nested Case-Control Study

The potential involvement of a sexually transmitted agent has been suggested to contribute to the high number of prostate cancers in the United States and worldwide. We investigated the relationship of Trichomonas vaginalis seropositivity with prostate cancer risk in a nested case-control study within the Multiethnic Cohort in Hawaii and California using blood samples collected prior to cancer diagnoses. Incident cases of advanced prostate cancer (intermediate- to high-grade based on Gleason score ≥ 7 and/or disease spread outside the prostate) were matched to controls by age, ethnicity, and the date of blood collection. T. vaginalis serostatus was measured using an ELISA detecting IgG antibodies against a recombinant T. vaginalis α-actinin protein. Seropositivity to T. vaginalis was observed in 35 of 470 (7.4%) cases and 26 of 470 (5.5%) controls (unadjusted OR = 1.47, 95% CI 0.82-2.64; adjusted OR = 1.31, 95% CI 0.67-2.53). The association was similarly not significant when cases were confined to extraprostatic tumors having regional or distant spread (n = 121) regardless of grade (unadjusted OR = 1.37, 95% CI 0.63-3.01; adjusted OR = 1.20, 95% CI 0.46-3.11). The association of T. vaginalis with prostate cancer risk did not vary by aspirin use. Our findings do not support a role for T. vaginalis in the etiology of advanced prostate cancer.

Dissecting Microbiome-Derived SCFAs in Prostate Cancer: Analyzing Gut Microbiota, Racial Disparities, and Epigenetic Mechanisms

Prostate cancer (PCa) continues to be the most diagnosed cancer and the second primary cause of fatalities in men globally. There is an abundance of scientific evidence suggesting that the human microbiome, together with its metabolites, plays a crucial role in carcinogenesis and has a significant impact on the efficacy of anticancer interventions in solid and hematological cancers. These anticancer interventions include chemotherapy, immune checkpoint inhibitors, and targeted therapies. Furthermore, the microbiome can influence systemic and local immune responses using numerous metabolites such as short-chain fatty acids (SCFAs). Despite the lack of scientific data in terms of the role of SCFAs in PCa pathogenesis, recent studies show that SCFAs have a profound impact on PCa progression. Several studies have reported racial/ethnic disparities in terms of bacterial content in the gut microbiome and SCFA composition. These studies explored microbiome and SCFA racial/ethnic disparities in cancers such as colorectal, colon, cervical, breast, and endometrial cancer. Notably, there are currently no published studies exploring microbiome/SCFA composition racial disparities and their role in PCa carcinogenesis. This review discusses the potential role of the microbiome in PCa development and progression. The involvement of microbiome-derived SCFAs in facilitating PCa carcinogenesis and their effect on PCa therapeutic response, particularly immunotherapy, are discussed. Racial/ethnic differences in microbiome composition and SCFA content in various cancers are also discussed. Lastly, the effects of SCFAs on PCa progression via epigenetic modifications is also discussed.

Insights into the Human Microbiome and Its Connections with Prostate Cancer

The human microbiome represents the diversity of microorganisms that live together at different organ sites, influencing various physiological processes and leading to pathological conditions, even carcinogenesis, in case of a chronic imbalance. Additionally, the link between organ-specific microbiota and cancer has attracted the interest of numerous studies and projects. In this review article, we address the important aspects regarding the role of gut, prostate, urinary and reproductive system, skin, and oral cavity colonizing microorganisms in prostate cancer development. Various bacteria, fungi, virus species, and other relevant agents with major implications in cancer occurrence and progression are also described. Some of them are assessed based on their values of prognostic or diagnostic biomarkers, while others are presented for their anti-cancer properties.

A matched case-control study in Taiwan to evaluate potential risk factors for prostate cancer

The rising incidence rate of prostate cancer (PCa) worldwide has become a public health concern. PCa has a multifactorial etiology, and the link between human papillomavirus (HPV) and PCa has been widely investigated by numerous case-control studies. This age-matched, case-control study included 143 PCa patients and 135 benign prostatic hyperplasia (BPH) patients, with prostatic specimens testing negative for malignancy, as control. Study participants were recruited from four major hospitals in Taoyuan City, Taiwan, period 2018-2020, looking into HPV infection and other PCa risk factors, including dietary habits, family history, personal lifestyle, and sexual behavior. Multiple logistic regression analysis and forward stepwise selection analysis were conducted to identify potential risk factors for PCa. HPV DNA was found in 10 of the 143 PCa cases (7%) and 2 of the 135 BPH controls (1.5%) (OR = 6.02, 95% CI = 1.03-30.3, p = 0.046). This association was slightly significant, and furthermore, high risk HPV was not found to be associated with PCa. Higher body mass index (BMI) (OR = 1.15, 95% CI = 1.05-1.27, p = 0.003), more total meat consumption (OR = 2.74, 95% CI = 1.26-5.94, p = 0.011), exhibited association to PCa. However, PCa family history only presented a statistically significant difference by forward stepwise analysis (OR = 3.91, 95% CI = 1.17-13.12, p = 0.027). While much focus has been on the association between HPV and PCa, the results of this study indicate that more efforts should be directed towards investigating dietary habits, personal lifestyle and family history as factors for PCa. These results could serve as a basis for designing PCa prevention strategies.

Multiple pathogens and prostate cancer

BACKGROUND

The aim of this review is to consider whether multiple pathogens have roles in prostate cancer.

METHODS

We have reviewed case control studies in which infectious pathogens in prostate cancer were compared to normal and benign prostate tissues. We also reviewed additional evidence from relevant published articles.

RESULTS

We confirmed that high risk human papilloma viruses are a probable cause of prostate cancer. We judged Escherichia coli, Cutibacterium acnes, Neisseria gonorrhoea, Herpes simplex, Epstein Barr virus and Mycoplasmas as each having possible but unproven roles in chronic prostatic inflammation and prostate cancer. We judged Cytomegalovirus, Chlamydia trachomatis, Trichomonas vaginalis and the Polyoma viruses as possible but unlikely to have a role in prostate cancer.

CONCLUSIONS AND ACTIONS

The most influential cause of prostate cancer appears to be infection induced chronic inflammation. Given the high prevalence of prostate cancer it is important for action to can be taken without waiting for additional conclusive evidence. These include: 1. Encouragement of all boys (as well as girls) to have HPV vaccines 2. The vigorous use of antibiotics to treat all bacterial pathogens identified in the urogenital tract 3. The use of antiviral medications to control herpes infections 4. Education about safe sexual practices.

Human herpesvirus 8 infection is associated with prostate cancer among IFNL4-ΔG carriers

Background

The dinucleotide germline variant, rs368234815-ΔG, in the IFNL4 gene (IFNL4-ΔG) has been associated with prostate cancer among men at increased risk of sexually transmitted infections and reported to impair viral clearance. Human herpesvirus 8 (HHV-8) seropositivity has been associated with prostate cancer in Tobago.

Methods

We examined whether the association of HHV-8 with prostate cancer is IFNL4-ΔG-dependent among 728 IFNL4-ΔG-genotyped cases and 813 genotyped population-based controls from the NCI-Maryland Prostate Cancer Case-Control study. Associations between HHV-8 and prostate cancer were assessed in multivariable unconditional logistic regression models. We calculated adjusted odds ratios (OR) and stratified the analysis into men harboring the IFNL4-ΔG-variant and non-carriers (ΔG/ΔG or ΔG/TT vs. TT/TT).

Results

HHV-8 seropositivity was higher in cases than controls (11% vs. 6%) and this association was restricted to carriers of the ΔG allele (OR 2.19: 95% CI:1.38–3.48) in both African American (OR 1.96; 95% CI:1.08–3.56) and European American men (OR 2.59; 95% CI:1.20–5.56).

Conclusions

HHV-8 seropositivity is associated with increased odds of prostate cancer in men harboring the IFNL4 rs368234815-ΔG variant. This study describes HHV-8 infection as a candidate prostate cancer risk factor in men with the IFNL4-ΔG genotype and supports the hypothesis that IFNL4-ΔG is a susceptibility factor that contributes to prostate cancer.

The microbiome and prostate cancer

There is growing evidence that the microbiome is involved in development and treatment of many human diseases, including prostate cancer. There are several potential pathways for microbiome-based mechanisms for the development of prostate cancer: direct impacts of microbes or microbial products in the prostate or the urine, and indirect impacts from microbes or microbial products in the gastrointestinal tract. Unique microbial signatures have been identified within the stool, oral cavity, tissue, urine, and blood of prostate cancer patients, but studies vary in their findings. Recent studies describe potential diagnostic and therapeutic applications of the microbiome, but further clinical investigation is needed. In this review, we explore the existing literature on the discovery of the human microbiome and its relationship to prostate cancer.

Prostate Microbiota and Prostate Cancer: A New Trend in Treatment

Although the incidence and mortality of prostate cancer have gradually begun to decline in the past few years, it is still one of the leading causes of death from malignant tumors in the world. The occurrence and development of prostate cancer are affected by race, family history, microenvironment, and other factors. In recent decades, more and more studies have confirmed that prostate microflora in the tumor microenvironment may play an important role in the occurrence, development, and prognosis of prostate cancer. Microorganisms or their metabolites may affect the occurrence and metastasis of cancer cells or regulate anti-cancer immune surveillance. In addition, the use of tumor microenvironment bacteria in interventional targeting therapy of tumors also shows a unique advantage. In this review, we introduce the pathway of microbiota into prostate cancer, focusing on the mechanism of microorganisms in tumorigenesis and development, as well as the prospect and significance of microorganisms as tumor biomarkers and tumor prevention and treatment.

Possible role of HPV/EBV coinfection in anoikis resistance and development in prostate cancer

BACKGROUND

This study aimed to evaluate the possible role of human papillomavirus (HPV) and Epstein-Barr virus (EBV) coinfection as an etiological factor for prostate cancer (PCa) development.

METHODS

This case-control study was conducted on 67 patients with PCa and 40 control subjects. The expression levels of cellular and viral factors involved in inflammation, tumor progression, and metastasis were quantified, using the enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR) assay.

RESULTS

The EBV/HPV coinfection was reported in 14.9% of patients in the case group and 7.5% of the control subjects. The high-risk types of HPV, that is, HPV 16 and HPV 18, were responsible for 50 and 30% of HPV/EBV-coinfected PCa cases (n = 10), respectively. No significant relationship was observed between PCa and HPV/EBV coinfection (OR = 2.9, 95% CI: 0.18-45.2, P = 0.31). However, the highest percentage of HPV genome integration was found in the HPV/EBV-coinfected PCa group (8/10; 80%). Also, the mean expression levels of inflammatory factors (IL-17, IL-6, TNF-α, NF-κB, VEGF, ROS, and RNS), anti-apoptotic mediators (Bcl-2 and survivin), and anti-anoikis factors (Twist and N-cadherin) were significantly higher in the HPV/EBV-coinfected PCa group, compared to the non-coinfected PCa cases. Nevertheless, the tumor-suppressor proteins (p53 and pRb) and E-cadherin (inhibitor of anoikis resistance) showed significant downregulations in the HPV/EBV-coinfected PCa group, compared to the non-coinfected PCa cases.

CONCLUSION

The HPV/EBV coinfection may be an etiological factor for PCa through modulation of cellular behaviors.

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.

Molecular detection of urogenital mollicutes in patients with invasive malignant prostate tumor

BACKGROUND

The etiology of prostate cancer (PCa) is multiple and complex. Among the causes recently cited are chronic infections engendered by microorganisms that often go unnoticed. A typical illustration of such a case is infection due to mollicutes bacteria. Generally known by their lurking nature, urogenital mollicutes are the most incriminated in PCa. This study was thus carried out in an attempt to establish the presence of these mollicutes by PCR in biopsies of confirmed PCa patients and to evaluate their prevalence.

METHODS

A total of 105 Formalin-Fixed Paraffin-Embedded prostate tissues collected from 50 patients suffering from PCa and 55 with benign prostate hyperplasia were subjected to PCR amplification targeting species-specific genes of 5 urogenital mollicutes species, Mycoplasma genitalium, M. hominis, M. fermentans, Ureaplasma parvum, and U. urealyticum. PCR products were then sequenced to confirm species identification. Results significance was statistically assessed using Chi-square and Odds ratio tests.

RESULTS

PCR amplification showed no positive results for M. genitalium, M. hominis, and M. fermentans in all tested patients. Strikingly, Ureaplasma spp. were detected among 30% (15/50) of PCa patients. Nucleotide sequencing further confirmed the identified ureaplasma species, which were distributed as follows: 7 individuals with only U. parvum, 5 with only U. urealyticum, and 3 co-infection cases. Association of the two ureaplasma species with PCa cases proved statistically significant (P < 0.05), and found to represent a risk factor. Of note, Ureaplasma spp. were mostly identified in patients aged 60 and above with prostatic specific antigen (PSA) level > 4 ng/ml and an invasive malignant prostate tumor (Gleason score 8-10).

CONCLUSIONS

This study uncovered a significant association of Ureaplasma spp. with PCa arguing in favour of their potential involvement in this condition. Yet, this finding, though statistically supported, warrants a thorough investigation at a much larger scale.

Interactive effect of TLR SNPs and exposure to sexually transmitted infections on prostate cancer risk in Jamaican men

BACKGROUND

Prostate cancer (PC) risk increases with African ancestry and a history of sexually transmitted infections (STIs). Also, single-nucleotide polymorphisms (SNPs) in toll-like receptor (TLR) genes influence PC risk. This pilot study explores interactions between STIs and TLR-related SNPs in relation to PC risk among Jamaican men.

METHODS

This case-control study evaluates two TLR related SNPs in 356 Jamaican men (194 controls and 162 cases) with or without history of STIs using stepwise penalized logistic regression in multivariable analyses.

RESULTS

Age (odds ratio [OR] = 1.08; 95% confidence interval [CI]: 1.04-1>.12; p < .001) and IRF3_rs2304206 GG genotype (OR = 0.47; 95% CI: 0.29-0<.78; p = .003) modulated PC risk in people with history of STIs. In the population with no history of STIs, resulting interactions between risk factors did not survive correction for multiple hypothesis testing.

CONCLUSION

Overall, an interaction between the IFR3_rs2304206 variant and a history of exposure to STIs leads to greater decrease of PC risk than the presence of polymorphic genotype alone. These findings are suggestive and require further validation. Identification of gene variants along with detection of lifestyle behaviors may contribute to identification of men at a greater risk of PC development in the population.

Evidence for a causal role by human papillomaviruses in prostate cancer - a systematic review

It is hypothesised that high risk for cancer human papillomaviruses (HPVs) have a causal role in prostate cancer.

In 26 case control studies, high risk HPVs have been identified in benign and prostate cancers. High risk HPVs were identified in 325 (22.6%) of 1284 prostate cancers and in 113 (8.6%) of 1313 normal or benign prostate controls (p = 0.001).

High risk HPVs of the same type have been identified in both normal and benign prostate tissues prior to the development of HPV positive prostate cancer. High risk HPVs can be associated with inflammatory prostatitis leading to benign prostate hyperplasia and later prostate cancer. Normal human prostate epithelial cells can be immortalised by experimental exposure to HPVs. HPVs are probably sexually transmitted.

The role of HPVs in prostate cancer is complex and differs from HPVs associated cervical cancer. HPV infections may initiate prostate oncogenesis directly and influence oncogenesis indirectly via APOBEC enzymes. HPVs may collaborate with other pathogens in prostate oncogenesis.

Although HPVs are only one of many pathogens that have been identified in prostate cancer, they are the only infectious pathogen which can be prevented by vaccination.

A causal role for HPVs in prostate cancer is highly likely.

Human microbiome and prostate cancer development: current insights into the prevention and treatment

The huge communities of microorganisms that symbiotically colonize humans are recognized as significant players in health and disease. The human microbiome may influence prostate cancer development. To date, several studies have focused on the effect of prostate infections as well as the composition of the human microbiome in relation to prostate cancer risk. Current studies suggest that the microbiota of men with prostate cancer significantly differs from that of healthy men, demonstrating that certain bacteria could be associated with cancer development as well as altered responses to treatment. In healthy individuals, the microbiome plays a crucial role in the maintenance of homeostasis of body metabolism. Dysbiosis may contribute to the emergence of health problems, including malignancy through affecting systemic immune responses and creating systemic inflammation, and changing serum hormone levels. In this review, we discuss recent data about how the microbes colonizing different parts of the human body including urinary tract, gastrointestinal tract, oral cavity, and skin might affect the risk of developing prostate cancer. Furthermore, we discuss strategies to target the microbiome for risk assessment, prevention, and treatment of prostate cancer.

Can epigenetic and inflammatory biomarkers identify clinically aggressive prostate cancer?

Prostate cancer (PCa) is a highly prevalent malignancy and constitutes a major cause of cancer-related morbidity and mortality. It emerges through the acquisition of genetic and epigenetic alterations. Epigenetic modifications include DNA methylation, histone modifications and microRNA deregulation. These generate heritable transformations in the expression of genes but do not change the DNA sequence. Alterations in DNA methylation (hypo and hypermethylation) are the most characterized in PCa. They lead to genomic instability and inadequate gene expression. Major and minor-specific modifications in chromatin recasting are involved in PCa, with signs suggesting a dysfunction of enzymes modified by histones. MicroRNA deregulation also contributes to the initiation of PCa, including involvement in androgen receptor signalization and apoptosis. The influence of inflammation on prostate tumor carcinogenesis is currently much better known. Recent discoveries about microbial species resident in the urinary tract suggest that these are the initiators of chronic inflammation, promoting prostate inflammatory atrophy and eventually leading to PCa. Complete characterization of the relationship between the urinary microbiome and prostatic chronic inflammation will be crucial to develop plans for the prevention of PCa. The prevalent nature of epigenetic and inflammatory alterations may provide potential biomarkers for PCa diagnosis, treatment decisions, evaluation of prognosis and posttreatment surveillance.

From Ancient to Emerging Infections: The Odyssey of Viruses in the Male Genital Tract

The male genital tract (MGT) is the target of a number of viral infections that can have deleterious consequences at the individual, offspring, and population levels. These consequences include infertility, cancers of male organs, transmission to the embryo/fetal development abnormalities, and sexual dissemination of major viral pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus. Lately, two emerging viruses, Zika and Ebola, have additionally revealed that the human MGT can constitute a reservoir for viruses cleared from peripheral circulation by the immune system, leading to their sexual transmission by cured men. This represents a concern for future epidemics and further underlines the need for a better understanding of the interplay between viruses and the MGT. We review here how viruses, from ancient viruses that integrated the germline during evolution through old viruses (e.g., papillomaviruses originating from Neanderthals) and more modern sexually transmitted infections (e.g., simian zoonotic HIV) to emerging viruses (e.g., Ebola and Zika) take advantage of genital tract colonization for horizontal dissemination, viral persistence, vertical transmission, and endogenization. The MGT immune responses to viruses and the impact of these infections are discussed. We summarize the latest data regarding the sources of viruses in semen and the complex role of this body fluid in sexual transmission. Finally, we introduce key animal findings that are relevant for our understanding of viral infection and persistence in the human MGT and suggest future research directions.

Emerging proteomics biomarkers and prostate cancer burden in Africa

Various biomarkers have emerged via high throughput omics-based approaches for use in diagnosis, treatment, and monitoring of prostate cancer. Many of these have yet to be demonstrated as having value in routine clinical practice. Moreover, there is a dearth of information on validation of these emerging prostate biomarkers within African cohorts, despite the huge burden and aggressiveness of prostate cancer in men of African descent. This review focusses of the global landmark achievements in prostate cancer proteomics biomarker discovery and the potential for clinical implementation of these biomarkers in Africa. Biomarker validation processes at the preclinical, translational and clinical research level are discussed here, as are the challenges and prospects for the evaluation and use of novel proteomic prostate cancer biomarkers.

The inflammatory microenvironment and microbiome in prostate cancer development

Chronic inflammation promotes the development of several types of solid cancers and might contribute to prostate carcinogenesis. This hypothesis partly originates in the frequent observation of inflammatory cells in the prostate microenvironment of adult men. Inflammation is associated with putative prostate cancer precursor lesions, termed proliferative inflammatory atrophy. Inflammation might drive prostate carcinogenesis via oxidative stress and generation of reactive oxygen species that induce mutagenesis. Additionally, inflammatory stress might cause epigenetic alterations that promote neoplastic transformation. Proliferative inflammatory atrophy is enriched for proliferative luminal epithelial cells of intermediate phenotype that might be prone to genomic alterations leading to prostatic intraepithelial neoplasia and prostate cancer. Studies in animals suggest that inflammatory changes in the prostate microenvironment contribute to reprogramming of prostate epithelial cells, a possible step in tumour initiation. Prostatic infection, concurrent with epithelial barrier disruption, might be a key driver of an inflammatory microenvironment; the discovery of a urinary microbiome indicates a potential source of frequent exposure of the prostate to a diverse number of microorganisms. Hence, current evidence suggests that inflammation and atrophy are involved in prostate carcinogenesis and suggests a role for the microbiome in establishing an inflammatory prostate microenvironment that might promote prostate cancer development and progression.

Role of antibodies to human papillomavirus 16 in prostate cancer: A seroscreening by peptide microarray

Evidence is accumulating in estimating the potential role of human papillomavirus infection in prostate carcinogenesis. However, the results remain inconclusive. We measured the serostatus of antibodies to one of the high-risk human papillomaviruses, human papillomavirus 16, with a newly developed peptide microarray. Serum samples were collected from 75 untreated prostate cancer patients, along with 80 control subjects. We identified 12 peptides with significant differences in prostate cancer samples from all 241 peptides derived from human papillomavirus 16. Our results showed human papillomavirus 16 infection in 64.0% of prostate cancer serum samples, which is significantly different compared with the controls ( p < 0.01) because only 17.5% of the control serum was considered seropositive. The area under the receiver operator characteristic curve was 0.793 (95% confidence interval 0.721-0.864), indicating that the new microarray technique may have diagnostic value. The results showed an association between serological evidence for human papillomavirus 16 infection and risk of prostate cancer. The different serostatus of antibodies in the two subgroups indicated that human papillomavirus 16 infection might occur and play a potential role of progression in a minority of prostate cancer.

Trichomonas vaginalis infection and risk of prostate cancer: associations by disease aggressiveness and race/ethnicity in the PLCO Trial

PURPOSE

Results from previous sero-epidemiologic studies of Trichomonas vaginalis infection and prostate cancer (PCa) support a positive association between this sexually transmitted infection and aggressive PCa. However, findings from previous studies are not entirely consistent, and only one has investigated the possible relation between T. vaginalis seropositivity and PCa in African-American men who are at highest risk of both infection and PCa. Therefore, we examined this possible relation in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, including separate analyses for aggressive PCa and African-American men.

METHODS

We included a sample of participants from a previous nested case-control study of PCa, as well as all additional Caucasian, aggressive, and African-American cases diagnosed since the previous study (total n = 438 Gleason 7 Caucasian cases, 487 more advanced Caucasian cases (≥Gleason 8 or stage III/IV), 201 African-American cases, and 1216 controls). We tested baseline sera for T. vaginalis antibodies.

RESULTS

No associations were observed for risk of Gleason 7 (odds ratio (OR) = 0.87, 95% confidence interval (CI) 0.55-1.37) or more advanced (OR = 0.90, 95% CI 0.58-1.38) PCa in Caucasian men, or for risk of any PCa (OR = 1.06, 95% CI 0.67-1.68) in African-American men.

CONCLUSIONS

Our findings do not support an association between T. vaginalis infection and PCa.

The PLCO Biorepository: Creating, Maintaining, and Administering a Unique Biospecimen Resource

Inclusion of biospecimens in population-based studies is an integral part of understanding disease etiology, identifying biomarkers and developing prevention and treatment strategies. The Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial collected, processed and stored biospecimens from participants to create a biorepository of specimens which serves as a useful resource for a broad research community. PLCO collected blood samples from consented screening arm participants at six screening rounds and a buccal sample from consented control arm participants. In addition, formalin-fixed paraffin embedded tumor tissue specimens were collected for participants in both arms for selected cancer sites. Collection of biospecimens at multiple timepoints (i.e. serial samples) and prior to cancer diagnosis, paired with rich epidemiologic and screening data, makes the PLCO collection of biospecimens a uniquely valuable resource. As such, access to the PLCO biorepository is granted to investigators by a rigorous scientific review process and guided by a steering committee which is responsible for developing and implementing the biospecimen use policies. Here, we describe the procedures for biospecimen collection, processing, storage, requisition, and distribution, as well as data management employed in PLCO. We also provide examples of how the biospecimens have been used to advance cancer research and describe relevant lessons learned to help inform cohorts wishing to add or modify biospecimen collection.

Epidemiology of Prostate Cancer

Prostate cancer is the most common malignancy among males worldwide, and is the second leading cause of cancer death among men in United States. According to GLOBOCAN (2012), an estimated 1.1 million new cases and 307,000 deaths were reported in 2012. The reasons for the increase of this disease are not known, but increasing life expectancy and modified diagnostic techniques have been suggested as causes. The established risk factors for this disease are advancing age, race, positive family history of prostate cancer and western diet (use of fat items). Several other risk factors, such as obesity, physical activity, sexual activity, smoking and occupation have been also associated with prostate cancer risk, but their roles in prostate cancer etiology remain uncertain. This mini-review aims to provide risk factors, disease knowledge, prevalence and awareness about prostate cancer.

Worldwide Prevalence of Human Papillomavirus and Relative Risk of Prostate Cancer: A Meta-analysis

Despite the increasing number of studies conducted recently to evaluate the association between HPV infections and the risk of prostate cancer, the results remain inconclusive. Furthermore, the prevalence and distribution of overall and individual HPV types worldwide in prostate cancer has not been reported until now. Therefore, we estimated the prevalence of HPV in prostate cancer by pooling data of 46 studies with 4919 prostate cancer cases, taking into account the heterogeneity of major related parameters, including study region, specimen type, HPV DNA source, detection method, publication calendar period and Gleason score. Moreover, we tested the association of HPV infections with prostate cancer risks by a meta-analysis of 26 tissue-based case-control studies. We found that the prevalence of HPV infection was 18.93% (95% CI = 17.84-20.05%) in prostate cancer cases, and most of which were high-risk HPV types (17.73%, 95% CI = 16.52-18.99%). The prevalence varied by region, PCR primers used, publication calendar period and Gleason score. Our study also showed a significantly increased risk of prostate cancer with the positivity of overall HPV detected in prostate tissues (OR = 1.79, 95% CI = 1.29-2.49) and revealed the geographic variation of association strength (P < 0.001). In conclusion, HPV infections may contribute to the risk of prostate cancer.

Persistence of Trichomonas vaginalis serostatus in men over time

PURPOSE

Previous epidemiologic studies have observed positive associations between Trichomonas vaginalis (Tv) serostatus and both prostate cancer (PCa) risk and mortality. However, only a few small older studies have examined Tv antibody persistence over time, all of which were composed mainly of female patients. Therefore, we examined Tv antibody persistence over time, as well as intra-individual variability, among middle- to older-aged men in the Southern Community Cohort Study (SCCS).

METHODS

We tested baseline and repeat plasma specimens (collected 1-3 years later) from 248 male participants for Tv antibodies. We used the same enzyme-linked immunosorbent assay as in previous studies of Tv serostatus and PCa.

RESULTS

At baseline, 46 (18.5 %) participants were seropositive for Tv infection. Seventy-six percent of these men were still seropositive 1-3 years later. A similar proportion of men "seroconverted" (4.0 %) as "seroreverted" (4.4 %), all of whom had absorbance values near the cutoff point for seropositivity. Overall, substantial agreement was observed between baseline and repeat serostatus (κ = 0.72, 95 % confidence interval 0.60-0.83).

CONCLUSION

Tv seropositivity was largely persistent between plasma specimens collected 1-3 years apart from middle- to older-aged men. These high levels of persistence are similar to those observed for other sexually transmitted infections frequently investigated in relation to PCa.

Gonorrhea and Prostate Cancer Incidence: An Updated Meta-Analysis of 21 Epidemiologic Studies

BACKGROUND

The association between gonorrhea and prostate cancer risk has been investigated widely, but the results remain inconsistent and contradictory. We conducted an updated meta-analysis to obtain a more precise estimate of this association.

MATERIAL AND METHODS

PubMed, EMBASE, and the Cochrane Library were searched for papers up to June 2014 to identify eligible studies. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the influence of gonorrhea on prostate cancer risk.

RESULTS

Twenty-one observational studies (19 case-control and 2 cohort) were eligible, comprising 9965 prostate cancer patients and 118 765 participants. Pooled results indicated that gonorrhea was significantly associated with increased incidence of prostate cancer (OR 1.31, 95% CI 1.14-1.52). The association between gonorrhea and prostate cancer was stronger in African American males (OR 1.32, 95% CI 1.06-1.65) than in Whites (OR 1.05, 95% CI 0.90-1.21).

CONCLUSIONS

Our findings suggest that gonorrhea is associated with an increased risk of prostate cancer, especially among African American males. These results warrant further well-designed, large-scale cohort studies to draw definitive conclusions.

Sexually transmitted infections, benign prostatic hyperplasia and lower urinary tract symptom-related outcomes: results from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial

OBJECTIVE

To examine whether a history of sexually transmitted infections (STIs) or positive STI serology is associated with prevalent and incident benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS)-related outcomes in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.

METHODS

Self-reported history of STIs (gonorrhoea, syphilis) was ascertained at baseline, and serological evidence of STIs (Chlamydia trachomatis, Trichomonas vaginalis, human papillomavirus (HPV)-16, HPV-18, herpes simplex virus type 2, human herpesvirus type 8 and cytomegalovirus) was detected in baseline serum specimens. We used data collected on the baseline questionnaire, as well as results from the baseline prostate-specific antigen (PSA) test and digital rectal examination (DRE), to define prevalent BPH/LUTS-related outcomes as evidence of LUTS (self-reported diagnosis of an enlarged prostate/BPH, BPH surgery or nocturia [waking ≥2 times/night to urinate]) and evidence of prostate enlargement (PSA > 1.4 ng/mL or prostate volume ≥30 mL) in men without prostate cancer. We created a similar definition of incident BPH using data from the follow-up questionnaire completed 5-13 years after enrolment (self-reported diagnosis of an enlarged prostate/BPH or nocturia), data on finasteride use during follow-up, and results from the follow-up PSA tests and DREs. We used Poisson regression with robust variance estimation to calculate prevalence ratios (PRs) in our cross-sectional analysis of self-reported (n = 32 900) and serologically detected STIs (n = 1 143) with prevalent BPH/LUTS, and risk ratios in our prospective analysis of self-reported STIs with incident BPH/LUTS (n = 5 226).

RESULTS

Generally null results were observed for associations of a self-reported history of STIs and positive STI serologies with prevalent and incident BPH/LUTS-related outcomes, with the possible exception of T. vaginalis infection. This STI was positively associated with prevalent nocturia (PR 1.36, 95% confidence interval (CI) 1.18-1.65), prevalent large prostate volume (PR 1.21 95% CI 1.02-1.43), and any prevalent BPH/LUTS (PR 1.32 95% CI 1.09-1.61); too few men had information on both STI serologies and incident BPH/LUTS to investigate the associations between T. vaginalis infection and incident BPH/LUTS-related outcomes.

CONCLUSIONS

Our findings do not support associations of several known STIs with BPH/LUTS-related outcomes, although T. vaginalis infection may warrant further study.

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.

Sexual partners, sexually transmitted infections, and prostate cancer risk

BACKGROUND

The etiology of prostate cancer (PCa) is poorly understood. Sexual activity and sexually transmitted infections (STIs) are among factors under scrutiny, with controversial findings to date.

METHODS

We examined the association between the number and gender of sexual partners, STIs and PCa risk in the context of PROtEuS, a population-based case-control study set amongst the mainly French-speaking population in Montreal, Canada. The study included 1590 histologically-confirmed PCa cases diagnosed in a Montreal French hospital between 2005 and 2009, and 1618 population controls ascertained from the French electoral list, Montreal residents, frequency-matched to cases by age. In-person interviews elicited information on sociodemographic, lifestyle and environmental factors. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between sexually related factors and PCa risk, adjusting for age, ancestry, family history of PCa, and PCa screening history.

RESULTS

Subjects with more than 20 sexual partners in their lifetime had a decreased risk of PCa (OR 0.78, 95% CI 0.61-1.00) as did subjects who specifically had more than 20 female sexual partners (OR 0.72, 95% CI 0.56-0.94). By contrast, having had several male sexual partners appeared to confer some excess in risk of PCa. No association emerged for history of STIs and PCa but STIs prevalence was low.

CONCLUSION

Our findings are in support of a role for the number of sexual partners in PCa development. The gender of sexual partners should be taken into account in future studies investigating this association.

Sexually transmitted infections and prostate cancer risk: a systematic review and meta-analysis

Prostate cancer (PC) is the second most incident cancer and the sixth cause of death by cancer in men worldwide. Despite extensive research efforts, no modifiable risk factors have been consistently identified for PC risk. A number of studies have focused on possible relationships between sexually transmitted infections (STIs) and PC. We performed a meta-analysis to explore the association between infection caused by Neisseria gonorrheae, Treponema pallidum, Chlamydia trachomatis, Trichomonas vaginalis, Ureaplasma urealyticum, Mycoplasma hominis, Herpes Simplex Virus types 1 and 2, Human Herpes Virus 8 and Cytomegalovirus, and PC. We conducted a comprehensive, systematic bibliographic search of medical literature to identify relevant studies. We calculated summary relative risk (SRR) and 95% confidence intervals (CI) for the association between each STI and PC through random effect models. Subgroup, meta-regression and sensitivity analyses were carried out to detect between-study heterogeneity and bias. We included 47 studies published between 1971 and 2011. Men who reported having ever had any STI in lifetime had an increased PC (SRR 1.49, 95% CI 1.19-1.92). We found a significantly increased PC risk in men having had gonorrhoea (SRR 1.20, 95% CI 1.05-1.37). No other single STI was significantly associated with PC. Due to high incidence of both STIs and PC worldwide, prevention of STIs may help preventing a considerable number of PC cases.

The role of prostatitis in prostate cancer: meta-analysis

Objective

Use systematic review methods to quantify the association between prostatitis and prostate cancer, under both fixed and random effects model.

Evidence Acquisition

Case control studies of prostate cancer with information on prostatitis history. All studies published between 1990-2012, were collected to calculate a pooled odds ratio. Selection criteria: the selection criteria are as follows: human case control studies; published from May 1990 to July 2012; containing number of prostatitis, and prostate cancer cases.

Evidence Synthesis

In total, 20 case control studies were included. A significant association between prostatitis and prostate cancer was found, under both fixed effect model (pooled OR=1.50, 95%CI: 1.39-1.62), and random effects model (OR=1.64, 95%CI: 1.36-1.98). Personal interview based case control studies showed a high level of association (fixed effect model: pooled OR=1.59, 95%CI: 1.47-1.73, random effects model: pooled OR= 1.87, 95%CI: 1.52-2.29), compared with clinical based studies (fixed effect model: pooled OR=1.05, 95%CI: 0.86-1.28, random effects model: pooled OR= 0.98, 95%CI: 0.67-1.45). Additionally, pooled ORs, were calculated for each decade. In a fixed effect model: 1990’s: OR=1.58, 95% CI: 1.35-1.84; 2000’s: OR=1.59, 95% CI: 1.40-1.79; 2010’s: OR=1.37, 95% CI: 1.22-1.56. In a random effects model: 1990’s: OR=1.98, 95% CI: 1.08-3.62; 2000’s: OR=1.64, 95% CI: 1.23-2.19; 2010’s: OR=1.34, 95% CI: 1.03-1.73. Finally a meta-analysis stratified by each country was conducted. In fixed effect models, U.S: pooled OR =1.45, 95%CI: 1.34-1.57; China: pooled OR =4.67, 95%CI: 3.08-7.07; Cuba: pooled OR =1.43, 95%CI: 1.00-2.04; Italy: pooled OR =0.61, 95%CI: 0.13-2.90. In random effects model, U.S: pooled OR=1.50, 95%CI: 1.25-1.80; China: pooled OR =4.67, 95%CI: 3.08-7.07; Cuba: pooled OR =1.43, 95%CI: 1.00-2.04; Italy: pooled OR =0.61, 95%CI: 0.13-2.90.CONCLUSIONS: the present meta-analysis provides the statistical evidence that the association between prostatitis and prostate cancer is significant.

Infections and inflammation in prostate cancer

The frequent observation of both acute and chronic inflammation of unknown stimulus in the adult prostate has motivated a large body of research aimed at identifying potential infectious agents that may elicit prostatic inflammation. The overarching hypothesis is that infection-induced inflammation may be associated with prostate cancer development or progression, as inflammation is known to serve as an "enabling characteristic" of cancer. With recent advances in molecular techniques for microorganism identification, a panoply of microorganisms has been scrutinized in prostate tissues and in relation to prostate carcinogenesis. The aim of this review is to summarize the current literature on the evidence for infectious agents as a contributing factor to prostatic inflammation and prostate cancer, and to highlight recent literature suggesting an infectious etiology to the biogenesis of prostatic corpora amylacea and on the development of mouse models of prostatic infections.

Increased risk of prostate cancer following sexually transmitted infection in an Asian population

The relationship between sexually transmitted infections (STIs) and prostate cancer (PC) remains inconclusive. Moreover, all such studies to date have been conducted in Western populations. This study aimed to investigate the risk of PC following STI using a population-based matched-cohort design in Taiwan. The study cohort comprised 1055 patients with STIs, and 10 550 randomly selected subjects were used as a comparison cohort. Cox proportional hazards regression analysis revealed that the hazard ratio for PC during the 5-year follow-up period for patients with a STI was 1.95 (95% confidence interval 1.18-3.23), that of comparison subjects after adjusting for urbanization level, geographical region, monthly income, hypertension, diabetes, hyperlipidaemia, obesity, chronic prostatitis, history of vasectomy, tobacco use disorder, and alcohol abuse. We concluded that the risk of PC was higher for men who were diagnosed with a STI in an Asian population.

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.

Prostate cancer and inflammation: the evidence

Chronic inflammation is now known to contribute to several forms of human cancer, with an estimated 20% of adult cancers attributable to chronic inflammatory conditions caused by infectious agents, chronic non-infectious inflammatory diseases and/or other environmental factors. Indeed, chronic inflammation is now regarded as an 'enabling characteristic' of human cancer. The aim of this review is to summarize the current literature on the evidence for a role for chronic inflammation in prostate cancer aetiology, with a specific focus on recent advances regarding the following: (i) potential stimuli for prostatic inflammation; (ii) prostate cancer immunobiology; (iii) inflammatory pathways and cytokines in prostate cancer risk and development; (iv) proliferative inflammatory atrophy (PIA) as a risk factor lesion to prostate cancer development; and (v) the role of nutritional or other anti-inflammatory compounds in reducing prostate cancer risk.

Inflammation and prostate carcinogenesis

Quite a few epidemiological studies including meta-analyses indicate that prostate inflammation is associated with increased risk of prostate cancer. The cause of inflammation in the prostate is speculated to be several microorganisms that cause prostatitis or sexually transmitted infections. Other specific microorganisms, such as xenotropic murine leukemia virus-related virus, are also reported to relate to the development of prostate cancer; however, the contribution of this microorganism to prostate cancer development needs to be carefully interpreted. Environmental factors, especially dietary factors, might also be associated with prostate cancer development. Among related dietary factors, charred meat carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine might be a link between environmental factors and inflammation, because 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine has the potential to accelerate prostate inflammation through its estrogenic effect. In light of these findings, preventing or reducing prostate inflammation might be one strategy for chemoprevention of prostate cancer.

Prospective study of cytomegalovirus serostatus and prostate cancer risk in the Prostate Cancer Prevention Trial

PURPOSE

To investigate serologic evidence of infection by cytomegalovirus (CMV), a herpesvirus with known oncogenic potential that has been detected in malignant prostate tissue, in relation to prostate cancer (PCa) risk in a large case-control study nested in the Prostate Cancer Prevention Trial (PCPT).

METHODS

Cases were men with a confirmed diagnosis of PCa after visit 2 (n = 614), and controls were men not diagnosed with PCa during the trial who also had a negative end-of-study biopsy (n = 616). Controls were frequency-matched to cases by age, treatment arm, and family history of PCa. Sera from visit 2 were tested for CMV IgG antibodies.

RESULTS

No association was observed between CMV serostatus and PCa risk (adjusted CMV seroprevalence = 67.9 % for cases and 65.2 % for controls, odds ratio = 1.13, 95 % CI 0.89-1.45).

CONCLUSIONS

Considering our null findings in the context of the full CMV literature, CMV infection, as measured by serostatus, does not appear to increase PCa risk.

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.

Age-specific human papillomavirus antibody and deoxyribonucleic acid prevalence: a global review

PURPOSE

Global data on human papillomavirus (HPV) serological and deoxyribonucleic acid (DNA) prevalence are essential to optimize HPV prophylactic vaccination strategies.

METHODS

We conducted a global review of age-specific HPV antibody and studies with both antibody and DNA prevalence for HPV-16, -18, -6, and -11.

RESULTS

One hundred seventeen studies were included; participants' ages ranged from several hours to >90 years. HPV-16 seroprevalence was generally higher in Africa, Central and South America, and North America, more prevalent among women than among men, and peaked around ages 25-40 years. HPV-18 seroprevalence was generally lower than HPV-16 with a later age peak. Data were limited for HPV-6 and -11, both of which peaked at ages similar to HPV-18. Among 9-26-year-old females, HPV-16 seroprevalence ranged from 0%-31% in North America, 21%-30% in Africa, 0%-23% in Asia/Australia, 0%-33% in Europe, and 13%-43% in Central and South America. HPV-16/-18 DNA prevalence peaked 10-15 years before corresponding HPV-16/-18 antibody prevalence.

CONCLUSIONS

Females within the HPV vaccine-eligible age-group (9-26 years) had a range of dual HPV-16 DNA and serology negativity from 81%-87%, whereas 90%-98% were HPV-16 DNA negative. Serology and DNA data are lacking worldwide for females younger than age 15 years, the prime target group for vaccination.

Risk factors for the onset of prostatic cancer: age, location, and behavioral correlates

At present, only three risk factors for prostate cancer have been firmly established; these are all nonmodifiable: age, race, and a positive family history of prostate cancer. However, numerous modifiable factors have also been implicated in the development of prostate cancer. In the current review, we summarize the epidemiologic data for age, location, and selected behavioral factors in relation to the onset of prostate cancer. Although the available data are not entirely consistent, possible preventative behavioral factors include increased physical activity, intakes of tomatoes, cruciferous vegetables, and soy. Factors that may enhance prostate cancer risk include frequent consumption of dairy products and, possibly, meat. By comparison, alcohol probably exerts no important influence on prostate cancer development. Similarly, dietary supplements are unlikely to protect against the onset of prostate cancer in healthy men. Several factors, such as smoking and obesity, show a weak association with prostate cancer incidence but a positive relation with prostate cancer mortality. Other factors, such as fish intake, also appear to be unassociated with incident prostate cancer but show an inverse relation with fatal prostate cancer. Such heterogeneity in the relationship between behavioral factors and nonadvanced, advanced, or fatal prostate cancers helps shed light on the carcinogenetic process because it discerns the impact of exposure on early and late stages of prostate cancer development. Inconsistent associations between behavioral factors and prostate cancer risk seen in previous studies may in part be due to uncontrolled detection bias because of current widespread use of prostate-specific antigen testing for prostate cancer, and the possibility that certain behavioral factors are systematically related to the likelihood of undergoing screening examinations. In addition, several genes may modify the study results, but data concerning specific gene-environment interactions are currently sparse. Despite large improvements in our understanding of prostate cancer risk factors in the past two decades, present knowledge does not allow definitive recommendations for specific preventative behavioral interventions.

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

Background

We previously reported a cross-sectional association between the presence of human herpesvirus 8 (HHV-8) serum antibodies and screen-detected prostate cancer in men living in Tobago. In the same study population, we examined the association between HHV-8 seropositivity and incident prostate cancer discovered at later screenings.

Methods

In 40-81 year-old men without prostate cancer discovered at initial digital rectal examination (DRE) and prostate-specific antigen (PSA) screening, a case-cohort design measured the association between baseline HHV-8 seropositivity (modified immunofluorescence assay for antibodies against HHV-8 lytic antigens) and incident prostate cancer detected at DRE and PSA screenings three or five years later.

Results

Analyses included 486 unique individuals, 96 incident prostate cancer cases, and 415 randomly selected subjects representing an at-risk cohort. By design, the random sub-cohort contained 25 incident prostate cancer cases. In the sub-cohort, the frequency of HHV-8 seropositivity increased across age groupings (40-49 years: 3.5%, 50-59 years: 13.6%, and ≥ 60 years: 22.9%). HHV-8 seropositivity was higher in men with elevated (≥ 4.0 ng/mL) than men with non-elevated PSA at initial screening (30.4% vs. 9.9% seropositive; crude odds ratio (OR) 3.96, 95% confidence interval (CI) 1.53-10.2; age-adjusted OR 2.42, 95% CI 0.91-6.47). HHV-8 seropositivity did not increase incident prostate cancer risk (age-adjusted hazard ratio (HR) 0.88, 95% CI 0.46-1.69).

Conclusions

Case-cohort analysis did not identify association between HHV-8 seropositivity and incident prostate cancer. However, analyses uncovered possible association between HHV-8 and PSA (a marker of prostate inflammation). Co-occurrence of HHV-8 seropositivity and PSA elevation may explain cross-sectional association between HHV-8 and PSA screen-detected prostate cancer.

Herpes simplex virus type 2 and cancer: a medical geography approach

Herpes simplex virus type-2 (HSV-2) has been identified as a possible aetiological agent of cancer in humans, especially prostate cancer, but results remain controversial. Here, we have addressed this question using a medical geography approach based on the national incidence of various cancers and seroprevalence of HSV-2 in 64 countries worldwide. We corrected reports of cancer incidence for national gross domestic product (GDP) because living in a wealthy nation likely increases the probability of having a cancer detected. Data were also corrected for latitude and diet. Our analysis not only confirms that prostate cancer and HSV-2 seroprevalence are positively associated, but it also reveals the existence of a positive relationship between HSV-2 and melanoma incidence in both men and women. These results, though correlational, suggest that HSV-2 should continue to be investigated as a possible oncogenic pathogen of humans.

Clinicopathologic features and determinants of Gleason score of prostate cancer in Ghanaian men

OBJECTIVE

Prostate cancer is reported to be more aggressive in Blacks. We studied the clinicopathologic features of prostate cancer in Ghana, in order to determine the factors responsible for them and to find out if there is any relationship between them.

METHOD

Patients referred with a biopsy proven diagnosis of carcinoma of the prostate to the Cancer Center of Korle Bu Teaching Hospital, Accra, Ghana, from 2003 to 2007 were studied. Information with respect to age at diagnosis, presenting symptoms, initial PSA (iPSA), Gleason score, and disease extent were studied. Age was partitioned into 50-65 and >65 years, Gleason score into 2-6, 7, and 8-10, iPSA into 4-20 ng/ml and >20, and disease extent into T1, T2, vs. T3, T4, M1, and the relationship between them was determined. Various presenting symptoms were described. Known risk factors and screening in a context of high grade disease is discussed.

RESULTS

A total of 170 patients were studied. Mean age was 65.4 years. Majority of patients (73.7%) presented with an iPSA > 20 ng/ml, whilst 22 (14.1%) had PSA < 10 ng/ml. Gleason score ≥ 7 was found in 95 (56%) of patients. Asymptomatic patients constituted 24.0%, the rest had bone pain (22.6%), urinary (50.4%), and neurologic symptoms (3.0%).There was a statistically significant relationship between age and Gleason score (P = 0.049), PSA and Gleason score (P = 0.0001), and between extent of disease and Gleason score (P = 0.0002). High fat diet and low intake of fruits and vegetables are probable risk factors in Ghana.

CONCLUSION

Majority of patients present with symptomatic disease at a relatively older age. These patients tend to have high Gleason score partly attributable to advanced disease, age, PSA at the time of diagnosis, and race. Screening with PSA should be recommended and individualized in this group of patients in order to allow diagnosis of less aggressive disease until better screening tools are identified.