The relationship of herpesvirus to carcinoma of the prostate

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.

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 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.

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.

Association of the innate immunity and inflammation pathway with advanced prostate cancer risk

Prostate cancer is the most frequent and second most lethal cancer in men in the United States. Innate immunity and inflammation may increase the risk of prostate cancer. To determine the role of innate immunity and inflammation in advanced prostate cancer, we investigated the association of 320 single nucleotide polymorphisms, located in 46 genes involved in this pathway, with disease risk using 494 cases with advanced disease and 536 controls from Cleveland, Ohio. Taken together, the whole pathway was associated with advanced prostate cancer risk (P = 0.02). Two sub-pathways (intracellular antiviral molecules and extracellular pattern recognition) and four genes in these sub-pathways (TLR1, TLR6, OAS1, and OAS2) were nominally associated with advanced prostate cancer risk and harbor several SNPs nominally associated with advanced prostate cancer risk. Our results suggest that the innate immunity and inflammation pathway may play a modest role in the etiology of advanced prostate cancer through multiple small effects.

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.

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.

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.

Serum antibodies against genitourinary infectious agents in prostate cancer and benign prostate hyperplasia patients: a case-control study

Background

Infection plays a role in the pathogenesis of many human malignancies. Whether prostate cancer (PCa) - an important health issue in the aging male population in the Western world - belongs to these conditions has been a matter of research since the 1970 s. Persistent serum antibodies are a proof of present or past infection. The aim of this study was to compare serum antibodies against genitourinary infectious agents between PCa patients and controls with benign prostate hyperplasia (BPH). We hypothesized that elevated serum antibody levels or higher seroprevalence in PCa patients would suggest an association of genitourinary infection in patient history and elevated PCa risk.

Methods

A total of 434 males who had undergone open prostate surgery in a single institution were included in the study: 329 PCa patients and 105 controls with BPH. The subjects' serum samples were analysed by means of enzyme-linked immunosorbent assay, complement fixation test and indirect immunofluorescence for the presence of antibodies against common genitourinary infectious agents: human papillomavirus (HPV) 6, 11, 16, 18, 31 and 33, herpes simplex virus (HSV) 1 and 2, human cytomegalovirus (CMV), Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Neisseria gonorrhoeae and Treponema pallidum. Antibody seroprevalence and mean serum antibody levels were compared between cases and controls. Tumour grade and stage were correlated with serological findings.

Results

PCa patients were more likely to harbour antibodies against Ureaplasma urealyticum (odds ratio (OR) 2.06; 95% confidence interval (CI) 1.08-4.28). Men with BPH were more often seropositive for HPV 18 and Chlamydia trachomatis (OR 0.23; 95% CI 0.09-0.61 and OR 0.45; 95% CI 0.21-0.99, respectively) and had higher mean serum CMV antibody levels than PCa patients (p = 0.0004). Among PCa patients, antibodies against HPV 6 were associated with a higher Gleason score (p = 0.0305).

Conclusions

Antibody seropositivity against the analyzed pathogens with the exception of Ureaplasma does not seem to be a risk factor for PCa pathogenesis. The presence or higher levels of serum antibodies against the genitourinary pathogens studied were not consistently associated with PCa. Serostatus was not a predictor of disease stage in the studied population.

Sexually transmitted infections and risk of prostate cancer: review of historical and emerging hypotheses

Since the early 1950s when sexually transmitted infections (STIs) were first proposed as a possible risk factor for prostate cancer, numerous epidemiologic studies have been conducted. Initially, these studies were primarily small case-control studies with retrospective, self-reported assessments of a narrow range of STIs, typically either any STIs, or gonorrhea and syphilis. However, as new STIs have been discovered/recognized, new and better tests to detect histories of STIs have been developed, and new resources for prostate cancer research have been created, epidemiologic studies have expanded to include a wide range of STIs, and have moved towards more rigorous, prospective study designs and serological assessment of STI histories. The results of these studies are reviewed and discussed, as well as possible new avenues of research, such as Trichomonas vaginalis infection and infections not typically considered to be sexually transmitted.

Sexually transmissible infections and prostate cancer risk

BACKGROUND

Sexually transmissible infections (STI) have been variably associated with increased risks of prostate cancer, largely in case-control studies.

METHODS

In the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, we examined risk of prostate cancer in relation to serum antibodies to Chlamydia trachomatis, human papillomavirus-16 and -18, herpes simplex virus-2, cytomegalovirus, and human herpesvirus-8 in 868 cases (765 Whites and 103 Blacks) and 1,283 controls matched by race, age, time since initial screening, and year of blood draw; all blood samples were collected at least 1 year before prostate cancer diagnosis, except for 43 Black cases. We also assessed risk associated with self-reported history of syphilis and gonorrhea.

RESULTS

Prevalences of the 7 STIs among controls were weakly correlated, and all were more frequent among Blacks than Whites, except for human herpesvirus-8. Among Whites, prostate cancer risk was not significantly associated with the individual infections or with their number (P(trend) = 0.1); however, men with one or more STI had slightly higher risk (odds ratio, 1.3; 95% confidence interval, 1.0-1.6). Among Blacks, excess risk was associated with IgA antibody to C. trachomatis (odds ratio, 2.1; 95% confidence interval, 1.2-3.6).

CONCLUSION

This large prospective study of prostate cancer shows no consistent association with specific STIs and a borderline association with any versus none. Whether a shared response or correlated infection not directly measured underlies the weak association requires further study.

Inflammation in the etiology of prostate cancer: an epidemiologic perspective

The epidemiologic literature on sexually transmitted infections, clinical prostatitis, prostatic calculi, polymorphisms in immune response genes, and nonsteroidal antiinflammatory drug use as potential sources and modifiers of intraprostatic inflammation is reviewed in relation to prostate cancer. Particular emphasis is placed on study methodology and its influence on study findings. Although evidence from reviewed epidemiologic studies, together with laboratory and clinical studies, is suggestive of a role for prostatic inflammation in the etiology of prostate cancer, additional large, prospective studies are necessary to address methodological limitations of existing studies, and to investigate a broader range of potential sources of intraprostatic inflammation.

Low frequency of BK virus in prostatic adenocarcinomas

BK virus (BKV) exhibits many oncogenic properties and has been associated with a variety of tumors in humans. BKV has not been well studied in the context of prostate neoplasia; however, an association of BKV with prostatic adenocarcinoma has been suggested based on the detection of viral DNA sequences and expression of viral proteins in clinical samples. To further investigate the reported association of BKV with prostatic adenocarcinoma and the potential role of the virus in prostate tumorigenesis, 30 cases of adenocarcinoma of the prostate were analyzed for evidence of BKV infection by in situ hybridization and immunohistochemistry. In situ hybridization analysis detected BKV DNA in 2 of 30 (7%) prostatic adenocarcinomas, with positive signals focally identified in less than 1% of the neoplastic cells in both cases. However, none of the tumors evaluated demonstrated evidence of BKV large tumor antigen expression by immunohistochemistry. Among prostatic adenocarcinomas that showed no evidence of BKV infection, BKV DNA was focally observed in the adjacent non-neoplastic prostate tissue in four cases by in situ hybridization in the absence of BKV large tumor antigen immunoreactivity. The findings of the present study indicate rare cases of prostatic adenocarcinoma may be associated with BKV infection. However, lack of localization of BKV to a large population of the neoplastic cells and absence of BKV large tumor antigen expression suggest that the virus does not play a role in the pathogenesis of prostate cancer.

Gonorrhea, syphilis, clinical prostatitis, and the risk of prostate cancer

BACKGROUND

Although previous case-control studies have observed positive associations among gonorrhea, syphilis, clinical prostatitis, and prostate cancer, many may have been susceptible to recall and interviewer biases due to their retrospective designs. Therefore, to investigate these associations without concerns of recall and interviewer biases, we conducted a large, prospective investigation in the Health Professionals Follow-up Study.

METHODS

In 1992, participants were asked to report their histories of gonorrhea, syphilis, and clinical prostatitis by mailed questionnaire. Prostate cancer diagnoses were ascertained by self-report on the 1994 and each subsequent biennial follow-up questionnaire and confirmed by medical record review.

RESULTS

Of the 36,033 participants in this analysis, 2,263 were diagnosed with prostate cancer between the date of return of the 1992 questionnaire and 2002. No association was observed between gonorrhea [adjusted relative risk (RR), 1.04; 95% confidence interval (95% CI), 0.79-1.36] or syphilis (RR, 1.06; 95% CI, 0.44-2.59) and prostate cancer. Overall null results were also observed between clinical prostatitis and prostate cancer (RR, 1.08; 95% CI, 0.96-1.20), although a significant positive association was observed among younger men (<59 years) screened for prostate cancer (RR, 1.49; 95% CI, 1.08-2.06; P(interaction) = 0.006).

CONCLUSIONS

Gonorrhea and syphilis do not seem to be risk factors for prostate cancer in this cohort of men with a lower burden of sexually transmitted infections. Clinical prostatitis is also unlikely to be a risk factor, although possible roles for prostatitis in younger men and asymptomatic prostatic infection and inflammation cannot be ruled out.

Adoption of a plant-based diet by patients with recurrent prostate cancer

The Western diet has been associated with prostate cancer incidence as well as risk of disease progression after treatment. Conversely, plant-based diets have been associated with decreased risks. A pilot clinical trial of a 6-month dietary change and stress reduction intervention for asymptomatic, hormonally untreated patients experiencing a consistently rising PSA level, the first sign of recurrence of prostate cancer after surgery or radiation therapy, was conducted to investigate the level of intake of plant-based foods and the relationship between intake and the change in the rate of PSA rise. A pre-post design was employed in which each patient served as his own control. In this multifaceted intervention, patients and their spouses were encouraged to adopt and maintain a plant-based diet. The prestudy rate of PSA rise (from the time of posttreatment recurrence to the start of the study) was ascertained by review of patients' medical records. Dietary assessments were performed and prostate-specific antigen (PSA) levels ascertained at baseline, prior to the start of intervention, and at 3 and 6 months. Changes in numbers of servings of plant-based food groups were calculated and compared with rates of PSA rise over the corresponding time intervals. Median intake of whole grains increased from 1.7 servings/d at baseline to 6.9 and 5.0 servings/d at 3 and 6 months, respectively. Median intake of vegetables increased from 2.8 servings/d at baseline to 5.0 and 4.8 servings/d at 3 and 6 months, respectively. The rate of PSA rise decreased when comparing the prestudy period (0.059) to the period from 0 to 3 months (-0.002, P < .01) and increased slightly, though not significantly, when comparing the period from 0 to 3 months to the period from 3 to 6 months (0.029, P = .4316). These results provide preliminary evidence that adoption of a plant-based diet is possible to achieve as well as to maintain for several months in patients with recurrent prostate cancer. Changes in the rate of rise in PSA, an indicator of disease progression, were in the opposite direction as changes in the intake of plant-based food groups, raising the provocative possibility that PSA may have inversely tracked intake of these foods and suggesting that adoption of a plant-based diet may have therapeutic potential in the management of this condition.

Prostate carcinogenesis and inflammation: emerging insights

Prostate cancer remains a significant health concern for men throughout the world. Recently, there has developed an expanding multidisciplinary body of literature suggesting a link between chronic inflammation and prostate cancer. In support of this hypothesis, population studies have found an increased relative risk of prostate cancer in men with a prior history of certain sexually transmitted infections or prostatitis. Furthermore, genetic epidemiological data have implicated germline variants of several genes associated with the immunological aspects of inflammation in modulating prostate cancer risk. The molecular pathogenesis of prostate cancer has been characterized by somatic alterations of genes involved in defenses against inflammatory damage and in tissue recovery. A novel putative prostate cancer precursor lesion, proliferative inflammatory atrophy, which shares some molecular traits with prostate intraepithelial neoplasia and prostate cancer, has been characterized. Here, we review the evidence associating chronic inflammation and prostate cancer and consider a number of animal models of prostate inflammation that should allow the elucidation of the mechanisms by which prostatic inflammation could lead to the initiation and progression of prostate cancer. These emerging insights into chronic inflammation in the etiology of prostate carcinogenesis hold the promise of spawning new diagnostic and therapeutic modalities for men with prostate cancer.

Prostatitis as a risk factor for prostate cancer

BACKGROUND

The association of infection or inflammation of the prostate with prostate cancer has been suggested but not established. This study was undertaken to investigate this association.

METHODS

Cases were Olmsted County, Minnesota, residents with histologically proven prostate cancer diagnosed between January 1980 and December 1996. Cases (n = 409) were each matched to 2 control subjects (n = 803) on age at diagnosis of prostate cancer, residency in Olmsted County, and duration of the community medical record. The medical record of each subject was reviewed for a history of acute or chronic bacterial prostatitis or chronic pelvic pain syndrome (inflammatory type).

RESULTS

The relative odds of prostate cancer were elevated in men with history of any type of prostatitis (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.1-2.6) or acute prostatitis (2.5; 1.3-4.7). The mean time from most recent episode of acute prostatitis to the diagnosis of prostate cancer was 12.2 years. After exclusion of men with acute prostatitis 2 years before the index date, the relationship was somewhat reduced (1.9; 0.9-3.8). Chronic bacterial prostatitis was more weakly associated with prostate cancer (1.6; 0.8-3.1), whereas chronic pelvic pain syndrome was not associated at all (0.9; 0.4-1.8).

CONCLUSIONS

Infection in the form of acute or chronic bacterial prostatitis may be associated with prostate cancer. However, our data do not provide compelling evidence to support this. As a result of the limitations of current methods of assessing chronic prostatitis, biochemical or tissue markers of infection or inflammation of the prostate may help clarify their role in the pathogenesis of prostate cancer.

Epidemiology of inflammation and prostate cancer

PURPOSE

We provide an overview of some of the basic, clinical and epidemiological research that has been conducted to investigate the potential role of chronic inflammation in prostate carcinogenesis and to provide direction for future research on this hypothesis.

MATERIALS AND METHODS

We reviewed the literature on this topic.

RESULTS

Chronic inflammation has long been linked to cancers with an infectious etiology, such as stomach, liver and colon cancer, in patients with inflammatory bowel disease. Whether intraprostatic inflammation contributes to prostate carcinogenesis is unknown. Inflammation is frequently present in prostate biopsies, radical prostatectomy specimens and tissue resected for treatment of benign prostatic hyperplasia. Also, inflammatory infiltrates are often found in and around foci of atrophy that are characterized by an increased proliferative index. These foci, called proliferative inflammatory atrophy, may be precursors of early prostate cancer or may indicate an intraprostatic environment favorable to cancer development. Epidemiological studies have indirectly examined the role of chronic inflammation in prostate carcinogenesis through studies of pro-inflammatory and anti-inflammatory factors. When taken together studies of sexually transmitted infections, clinical prostatitis, and genetic and circulating markers of inflammation and response to infection hint at a link between chronic intraprostatic inflammation and prostate cancer.

CONCLUSIONS

Additional well-designed basic, clinical and epidemiological studies are needed to resolve questions about the role of chronic inflammation in prostate carcinogenesis and to determine if intraprostatic inflammation is a rational target for chemoprevention.

Epidemiologic association between prostatitis and prostate cancer

OBJECTIVES

To quantify the relationship between prostatitis and prostate cancer by pooling previous epidemiologic studies of this association.

METHODS

A comprehensive search for articles published through 2000 was performed, blinded reviews of each study were conducted, data were abstracted, and all such studies were pooled.

RESULTS

In this meta-analysis, an increased risk was seen among men with a history of prostatitis (odds ratio = 1.6), particularly with population-based case-control studies (odds ratio = 1.8). Increased relative risk estimates were also seen among men with a history of syphilis and a history of gonorrhea.

CONCLUSIONS

These associations with prostate cancer suggest that infections may represent one mechanism through which prostate cancer develops. However, causality is unclear, because recall bias and detection bias cannot be ruled out. Future cohort studies of prostate cancer should examine sexually transmitted infections, as well as other infections, as potential risk factors.

Meta-analysis of measures of sexual activity and prostate cancer

We conducted a meta-analysis of the association between prostate cancer and aspects of sexual activity. The data suggest an elevated relative risk (RR) of prostate cancer among men with a history of sexually transmitted infections. This was observed with both random- and fixed-effects models (RR = 1.4; 95% CI = 1.2-1.7; N = 17 studies; heterogeneity P = 0.14), especially for syphilis (RR = 2.3; 95% CI = 1.3-3.9; N = 6; heterogeneity P = 0.47). Risk of prostate cancer is also associated with increasing frequency of sexual activity (RR = 1.2 for an increase of three times per week; 95% CI = 1.1-1.3; N = 12). However, these studies are heterogeneous (P < 0.001). Increasing number of sexual partners is also associated with prostate cancer (RR = 1.2 for an increase of 20 partners; 95% CI = 1.1-1.3; N = 16; heterogeneity P = 0.11). The data do not support associations with multiple marriages, age at first intercourse, or age at first marriage. These results indicate an association between prostate cancer and sexually transmitted infections, suggesting that infections may represent one mechanism through which prostate cancer develops. The mechanism through which frequency of sexual activity may be related to prostate cancer is unclear.

Viruses in the mammalian male genital tract and their effects on the reproductive system

This review describes the various viruses identified in the semen and reproductive tracts of mammals (including humans), their distribution in tissues and fluids, their possible cell targets, and the functional consequences of their infectivity on the reproductive and endocrine systems. The consequences of these viral infections on the reproductive tract and semen can be extremely serious in terms of organ integrity, development of pathological and cancerous processes, and transmission of diseases. Furthermore, of essential importance is the fact that viral infection of the testicular cells may result not only in changes in testicular function, a serious risk for the fertility and general health of the individual (such as a fall in testosteronemia leading to cachexia), but also in the possible transmission of virus-induced mutations to subsequent generations. In addition to providing an exhaustive account of the data available in these domains, this review focuses attention on the fact that the interface between endocrinology and virology has so far been poorly explored, particularly when major health, social and economical problems are posed. Our conclusions highlight the research strategies that need to be developed. Progress in all these domains is essential for the development of new treatment strategies to eradicate viruses and to correct the virus-induced dysfunction of the endocrine system.

Sexual behaviour, STDs and risks for prostate cancer

A population-based case-control study was carried out among 981 men (479 black, 502 white) with pathologically confirmed prostate cancer and 1315 controls (594 black, 721 white). In-person interviews elicited information on sexual behaviour and other potential risk factors for prostate cancer. Blood was drawn for serologic studies in a subset of the cases (n = 276) and controls (n = 295). Prostate cancer risk was increased among men who reported a history of gonorrhoea or syphilis (odds ratio (OR) = 1.6; 95% confidence internal (CI) 1.2-2.1) or showed serological evidence of syphilis (MHA-TP) (OR = 1.8; 95% CI 1.0-3.5). Patterns of risk for gonorrhoea and syphilis were similar for blacks (OR = 1.7; 95% CI 1.2-2.2) and whites (OR = 1.6; 95% CI 0.8-3.2). Risks increased with increasing occurrences of gonorrhoea, rising to OR = 3.3 (95% CI 1.4-7.8) among subjects with three or more events (Ptrend = 0.0005). Frequent sexual encounters with prostitutes and failure to use condoms were also associated with increased risk. Syphilis, gonorrhoea, sex with prostitutes and unprotected sexual intercourse may be indicators of contact with a sexually transmissible factor that increases the risk of prostate cancer.

The importance of marital and socioeconomic status in incidence and survival of prostate cancer. An analysis of complete Norwegian birth cohorts

BACKGROUND

Previous studies of the association between social and family status and prostate cancer (PCa) have given somewhat divergent results. Little attention has been paid to the possible importance of these factors for survival.

METHODS

In this study, hazard regression models for PCa incidence and mortality were estimated on the basis of register- and census-based histories for complete Norwegian birth cohorts, giving a follow-up time of 16 million person years and 30,000 cases of PCa.

RESULTS

A significant excess incidence of about 20% was found for ever-married men and for those with higher education. Marriage and socioeconomic resources appeared, however, to have a favorable effect on survival. Five-year relative survival from metastasized cancer among men with a high educational level was found to be 15 percentage points higher than among men with lower education.

CONCLUSIONS

The observed differences in incidence are not easily explained. They apparently run counter to the hypothesis that multiple partners give a higher PCa risk, but may be consistent with the view that fat and meat consumption is risky. Better survival from PCa in higher socioeconomic groups and among married men may reflect differences in the search for, access to, or quality of treatment or a better constitution to fight the disease.

Detection of human papillomavirus in the prostate by polymerase chain reaction and in situ hybridization

Human papillomavirus is associated with a variety of anogenital lesions, including genital warts, precancers and cancers. In male patients human papillomavirus has been identified in proliferative lesions ranging from penile and urethral warts to penile and prostatic cancers. We examined the association of human papillomavirus deoxyribonucleic acid (DNA) in 84 prostate tissue specimens. Specimens were selected from radical prostatectomy, transurethral resection or transrectal biopsy procedures. A total of 60 formalin-fixed, paraffin-embedded tissues (24 prostate cancer specimens, 16 benign prostatic hyperplasia specimens and 20 normal specimens) was examined by polymerase chain reaction and in situ hybridization. Also, 24 gelatin-embedded frozen prostate cancer specimens were examined for human papillomavirus DNA by polymerase chain reaction. Of the specimens 69 were deemed adequate for polymerase chain reaction analysis, whereas all 60 paraffin-embedded tissues were sufficient for in situ hybridization. Human papillomavirus DNA was detected in 2 normal tissues and 6 prostate cancers using polymerase chain reaction. None of the benign prostatic hyperplasia specimens was positive for human papillomavirus. Human papillomavirus typing results indicated that virus type 16 was present in each of the 8 positive specimens. Confirmation of the presence of human papillomavirus was obtained for 1 of the prostate cancers by nonisotopic in situ hybridization with biotinylated human papillomavirus genomic probes. The low prevalence of human papillomavirus in this study population does not strongly support an etiological role for the virus in prostate cancer.

Prostate cancer

Prostate cancer is the most common malignancy in men and the second leading cause of cancer deaths. Although the mortality rate for prostate cancer has remained unchanged for 50 years, new advances have changed classic concepts in the diagnosis and management of patients with this disease. Our understanding of the anatomy and natural history of patients with prostate cancer has been enhanced. The ability to diagnose early stage prostate tumors has been improved by the introduction of prostate-specific antigen and transrectal ultrasound. Clinical staging of patients with prostate cancer has been refined, which has decreased adverse effects of inappropriate treatment. Modifications in the technique of radical prostatectomy have minimized the morbidity associated with this procedure, making it a more attractive therapeutic option. DNA ploidy analysis holds promise as a predictor of response to hormonal therapy. New agents are available to reduce adverse effects of hormonal therapy. In addition, traditional ideas about the timing of hormonal therapy and the use of total androgen blockade are being challenged. These changes may presage an improved quality of life and improve survival for patients with prostate cancer.

High prevalence of human papillomavirus in prostate tissues

Specific human papillomavirus (HPV) types are associated with benign and malignant lesions of the anogenital region including the prostate gland. Using polymerase chain reaction (PCR) amplification of type-specific HPV sequences, we have assessed the prevalence of HPV DNA in prostate tissue from 88 individuals. Amplified sequences specific for HPV 16 were found in 34 of 56 benign prostatic hyperplasias and in 14 of 27 prostatic carcinomas. In contrast, HPV 18 was identified in only three benign hyperplasias and one carcinoma, all of which also contained HPV 16 DNA. Four of five normal prostates obtained at autopsy had no detectable HPV infection; one contained HPV 16 sequences. No significant difference in the prevalence of HPV DNA is observed between patients with benign disease and those with evidence of malignancy when fragments of surgical material are analyzed. Surgical method (transurethral resection or suprapubic prostatectomy) had no effect on the frequency of HPV detection. The prevalence of HPV DNA in the small number of normal prostates analyzed was not significantly different from that in the surgical samples. The presence of HPV in prostate tissues suggests a possible reservoir for sexual transmission of types with oncogenic potential. A role for the virus in the etiology of prostatic neoplasia remains to be demonstrated.

Update in the management of prostate cancer

Prostate cancer remains one of the commonest malignancies in our community, and it appears that its incidence is rising because of the increasing proportion of the aged population. Improved technology, including the development of new tumour markers and tumour imaging techniques, and a gradually increasing community awareness of this disease, may allow earlier diagnosis. In turn, as the proportion of patients presenting with early stage disease increases, improved approaches to the treatment of localized cancer may thus yield increased community cure rates. The mainstay of treatment of advanced disease remains hormonal manipulation. The introduction of the LHRH agonists has provided an alternative to surgical castration, but has not resulted in an improved response rate or survival from first-line therapy. We believe that these agents do not offer a major benefit, when compared with the simple procedure of orchidectomy, notwithstanding the psychological sequelae of castration. With a median survival of less than five years after hormonal manipulation, many patients still require salvage treatment after relapse. New hormonal therapies yield objective and subjective response rates of approximately 15% and 30%, respectively, but the median survival from the time of hormonal failure remains less than one year. Cytotoxic chemotherapy has not provided a panacea, but has shown definite evidence of antitumour activity in this disease. The use of relatively non-toxic single cytotoxic drugs can provide effective palliation of symptoms in up to 40% of patients and may even prolong survival in some patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Monoclonal antibodies to HSV-infection-related antigens cross-react with tumor cell lines and tumor tissue sections

The purpose of our study was to evaluate a possible association between herpes simplex virus (HSV) and various tumors, including oral squamous cell carcinoma (SCC). To this end, we tested the binding of appropriate monoclonal antibodies to a panel of cell lines and tumor sections. The 25 monoclonal antibodies were reactive with HSV-infected cells but not with uninfected cells. Of these antibodies, three bound to several SCC cell lines and to one non-SCC cell line (K562). One of these three antibodies also reacted with sections of oral SCC tumors, the adjacent mucosa, and normal esophageal epithelium. In contrast, it did not bind to sections of kidney, spleen, esophageal smooth muscle, and skin. To evaluate whether the observed antibody binding could reflect an actual infection by HSV, hybridization experiments between K562 DNA and HSV DNA were performed. HSV DNA sequences were found in K562 DNA at a ratio of 0.1 genome-equivalents/cell. Although these data do not characterize the nature of the relationship, they clearly confirm the postulated association of HSV with some tumors (in particular oral SCC).

Oncogenic potential of sexually transmitted viruses with special reference to oral cancer

Recent changes in social mores have been accompanied by a noted increase in the frequency of sexually transmitted diseases. Viruses that have been identified as causative agents for a large proportion of these diseases have also been associated with various malignant states. Concomitantly, the number of cases of oral cancer (considered to occur usually around or after the fifth decade of life) reportedly has been increasing among young adults. The oncogenic potential of several sexually transmitted viruses (HSV, HPV, CMV, and LAV/HTLV III) and their possible role in the development of malignant conditions, in particular oral cancer, are discussed in this review.

Review: prostate cancer epidemiology

Prostate cancer is common among men in the United States. Factors of possible importance in the etiology of prostate cancer include diet, primarily implicated by ecologic studies of national, regional, and ethnic variation in rates; endocrine function, implicated by the importance of endocrine function in normal prostatic growth and in the treatment of prostate cancer; genetic susceptibility, supported by familial aggregation; some aspect of sexual behavior, suggested by case-control differences in sexual behavior; and occupational exposure, particularly cadmium exposure. Despite the public health importance of prostate cancer, it has received only moderate epidemiologic study; thus the etiologic importance of these and other possible determinants of prostate cancer risk is uncertain [55].