Human papillomavirus 16 infection as a potential risk factor for prostate cancer: an adaptive meta-analysis

Presence of HPV in prostate tissue from patients submitted to prostate biopsy

PURPOSE

Prostate cancer (PCa) is the second most frequent cancer among men in the Western population. Infections, such as the one caused by the human papillomavirus (HPV), have been shown to promote inflammation that can lead to the appearance of neoplasms. This study aimed to verify the presence of HPV in neoplastic and non-neoplastic prostate tissue in patients undergoing prostate biopsy and its possible relationship with PCa.

METHODS

Prostate tissue fragments were collected by prostate biopsy and subjected to polymerase chain reaction with primers for the HPV L1 gene to identify the presence of the virus.

RESULTS

Among 162 patients, 10 (6.2%) had HPV and in 152 (93.8%) HPV was not identified in prostate biopsies. HPV was detected in 7/95 (7.4%) of patients with PCa, in 2/55 (3.6%) of patients without PCa, and in no patient with an inconclusive diagnosis of PCa. There was no significant difference (p = 0.487) of HPV presence in the tissue of patients with PCa.

CONCLUSIONS

There were no significant levels of HPV L1 protein in prostate tissue. The findings suggest the absence of HPV oncogenic activity in the prostate tissue of patients with PCa.

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.

Knowledge, attitudes, and practices among Indonesian urban communities regarding HPV infection, cervical cancer, and HPV vaccination

Background

Few studies explored Indonesian understanding of cervical cancer (CC) and the human papillomavirus (HPV) vaccination. We aimed to investigate the association between knowledge, attitudes, and practices (KAP) and socio-demographical influences related to HPV, CC, and vaccination among Indonesian urban citizens.

Methods

We conducted an online survey during March 2020-August 2021 using the Snowball sampling technique. The socio-demographic characteristic and KAP responses were collected via Google Forms from 400 respondents in Jakarta. The knowledge and attitudes were divided into HPV and CC (aspect 1) and HPV vaccination (aspect 2). Correlation between KAP scores was performed using Spearman’s test, and multiple logistic regression analyses were conducted to determine KAP predictors.

Results

Indonesian urban citizens in Jakarta were found to have poor knowledge in individual aspects of the inquiry but moderate knowledge overall, good attitude in inquiry both in each aspect and overall, and unsatisfying practices. Overall, in the general population, men, and women respectively: 50.8%, 32.4%, and 53.6% had good knowledge; 82.0%, 75.2%, and 84.4% expressed positive attitude; and 30.3%, 15.2%, and 35.6% applied favorable practice regarding questions inquired. Knowledge was weakly correlated towards attitude (ρ = 0.385) but moderately correlated with practice (ρ = 0.485); attitude was moderately correlated with practice (ρ = 0.577), all results: p<0.001. Significant odds ratio (OR) for predictors to good knowledge were female sex (OR = 2.99), higher education (OR = 2.91), and higher mother’s education (OR = 2.15). Factors related to positive attitudes were higher mother’s education (OR = 4.13), younger age (OR = 1.86), and better results in the knowledge inquiries (OR = 2.96). Factors that suggested better practices were female sex (OR = 2.33), being employed (OR = 1.68), excellent knowledge scores (OR = 4.56), and positive attitudes expressions (OR = 8.05). Having done one vaccination dose and intention to receive vaccines were significantly influenced by good KAP.

Conclusions

KAP had inter-association to successful CC and HPV prevention programs, and socio-demographical characteristics are critical to influencing better KAP.

Molecular characterization of human papillomavirus and mouse mammary tumor virus‑like infections in prostate cancer tissue and relevance with tumor characteristics

The suspected roles of human Papillomavirus (HPV) and mouse mammary tumor virus (MMTV) infections in prostate tumor development were recently reported. To detect the frequency of HPV and MMTV-like infections and clinical correlates of tumor characteristics, DNA samples from 50 men treated at Teaching Hospital of Rabat City (Morocco) between June 2017 and February 2019, were genotyped and confirmed by Sanger sequencing. Eight infections of HPV18 and two infections of MMTV-like were detected, and 50% of patients were at a Gleason score of 6. A significant association between Gleason score and HPV or MMTV-like infection was noted (P=0.0008); 90% of patients with viral infections presented with T1 and T2 pathological stage tumors. Yet, no significant differences were found between infected and noninfected men regarding other pathological parameters including prostate-specific antigen (PSA), tumor histological stage, age at diagnosis and radical prostatectomy treatment (P=0.2179, 0.4702, 0.8101, and 0.9644, respectively). The molecular evolution of HPV and MMTV in comparison with previously aligned sequences was discussed. Our findings provide a highlight on the correlations between the clinical-pathological parameters of prostate tumors and HPV and MMTV infections. Prospective studies with a wide sample size are needed for more statistical clarification of the association between viral infections with prostate tumor criteria.

The Roles of the Virome in Cancer

Viral infections as well as changes in the composition of the intestinal microbiota and virome have been linked to cancer. Moreover, the success of cancer immunotherapy with checkpoint inhibitors has been correlated with the intestinal microbial composition of patients. The transfer of feces-which contain mainly bacteria and their viruses (phages)-from immunotherapy responders to non-responders, known as fecal microbiota transplantation (FMT), has been shown to be able to convert some non-responders to responders. Since phages may also increase the response to immunotherapy, for example by inducing T cells cross-reacting with cancer antigens, modulating phage populations may provide a new avenue to improve immunotherapy responsiveness. In this review, we summarize the current knowledge on the human virome and its links to cancer, and discuss the potential utility of bacteriophages in increasing the responder rate for cancer immunotherapy.

Human papilloma virus: A review study of epidemiology, carcinogenesis, diagnostic methods, and treatment of all HPV-related cancers

Background: Human papillomavirus (HPV) infection is considered as the most common viral sexually transmitted infection worldwide. This poses an increasingly interdisciplinary medical challenge. Since there is vast scattered information in databases about HPV and the correlated diseases, we decided to collect useful data so that the experts can get a more comprehensive view of HPV. Methods: In this article, HPV-associated diseases, prevalence, prevention, and new treatments are discussed. The retrieved articles reporting the latest data about the required information for our review were selected through searching in Web of Science, Scopus, Medline (PubMed), EMBASE, Cochrane Library, Ovid, and CINHAL with language limitations of English and German. Results: There are 2 groups of HPVs: (1) low-risk HPV types that can lead to genital warts, and (2) high-risk HPV types that are involved in HPV-associated oncogenesis. About 70% of all sexually active women are infected and most of these infections heal within many weeks or months. In the case of HPV-persistence, a risk of preneoplasia or carcinoma exists. These types of viruses are responsible for the existence of genitoanal, gastrointestinal, urinary tract, and head and neck tumors. There is still no definite successful treatment. The detection of HPV-related condylomata occurs macroscopically in women and men, and the diagnosis of the precursors of cervical carcinoma in women is possible by Pap smear. Conclusion: For extragenital manifestations, there is no structured early detection program. Meanwhile, studies on HPV vaccines confirm that they should be used for the primary prevention of HPV-dependent diseases. However, we need more research to find out the real advantages and disadvantages of vaccines.

Prevalence of Human Papillomavirus (HPV) DNA among Men with Oropharyngeal and Anogenital Cancers: A Systematic Review and Meta-Analysis

OBJECTIVE

The term ''Human Papillomavirus'' or ''HPV'' has become synonymous with uterine cervical cancer leading to feminisation of all the preventive measures, especially immunisation. Taking into consideration the rising number of HPV associated cancers among men in many developed countries and the risk of transmission to women, male HPV infection is a serious concern. A systematic review and meta-analysis of literature was performed to determine the global prevalence of HPV among men with oropharyngeal and anogenital cancers.

METHODS

A systematic review and meta-analysis of literature was performed searching electronic databases for published articles in English between January 1984- April 2020 based on standard systematic review guidelines. The meta-analysis component was modified appropriately for the synthesis of prevalence study results. National Institutes of Health checklist for observational, cohort and cross-sectional studies was used to assess the quality of the studies selected after the abstract and content review. The meta-analysis was performed in STATA version 13.0 (College Station, Texas 77,845 USA) and the forest plots were constructed using metan package in STATA.

RESULTS

Through the electronic search of databases, 3486 original articles were screened for eligibility. Fifty-eight articles were systematically reviewed and 42 articles were qualified for meta-analysis including 4,250 men with oropharyngeal, penile and prostate cancers. The pooled prevalence of HPV DNA in oropharyngeal cancers was 45% (95%CI 24.0%-66.0%). Meanwhile the pooled prevalence rates of 48% (CI 40.0%- 57.0%) and 19% (CI 10.0%-29.0%) were observed in penile and prostate cancers respectively. Even though, articles regarding HPV prevalence in anal cancers were systematically reviewed, none of the studies were qualified for meta-analysis.

CONCLUSION

Higher pooled prevalence of HPV DNA was observed among men with oropharyngeal and penile cancers. Multicentric molecular studies investigating the prevalence of HPV in prostate cancers have to be planned in future.

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 papillomavirus and risk of prostate cancer: a systematic review and meta-analysis

Background: There is growing evidence showing a putative association between high-risk human papillomavirus (HR-HPV) infection and an increased risk of PCa.Objective: The aim of the current meta-analysis was to evaluate the association between HPV infection and PCa risk.Methods: This analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. We included all studies on HPV DNA or antibodies detected in biopsy tissues or sera. Available data were extracted from the article, including means and standard deviations in all case-control groups.Results: Thirty studies that investigated the link between HPV-16 and -18 were identified as eligible for this systematic review and meta-analysis, including a total of 6321 participants. The pooled OR showed increased risk of PCa (OR =1.37; p < .01) in men positive for HPV-16. There were seven studies with 2391 PCa cases and 4059 controls investigating the association between HPV-18 infection and PCa risk. Significant heterogeneity between study was found in the pooled analyzes. The pooled OR did not show increased risk of PCa (OR =0.80; p = .49) in men positive for HPV-18.Conclusions: This meta-analysis suggests that HPV-16 infection could represent a risk factor for PCa, whereas we found no such association for HPV-18. Further well-conducted studies could be useful to confirm this conclusion.

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.

Retracted: Identification of Prognosis Biomarkers of Prostatic Cancer in a Cohort of 498 Patients from TCGA

The article entitled, "Identification of prognosis biomarkers of prostatic cancer in a cohort of 498 patients from TCGA," by Chen Z and Hu H. (J Comput Biol Dec 2019: e-pub ahead of print; DOI: 10.1089/cmb.2019.0224) is being officially retracted at the authors' request due to errors found in the data after publication of the article. The detected errors render the results and conclusion irreproducible, and therefore, invalid. Based on the communications received from the authors, the editorial leadership of Journal of Computational Biology agreed to retract the published paper. However, after retracting the article, it was also discovered that the same article had been previously published in volume 43, issue 6 of the journal, Current Problems in Cancer, published by Elsevier. The publisher of Journal of Computational Biology was in communication with Elseivier since simultaneous submission and/or publication is a violation of the proper protocols of peer review, and they are conducting their own evaluation. Journal of Computational Biology also notified the authors' institution of the infraction. Journal of Computational Biology, its Editor, and its Publisher are committed to preserving the integrity of the scientific record for the community it serves.

Association between HPV infection and prostate cancer in a Mexican population

The aim of this study was to evaluate the association between prostate cancer (PCa) and Human papillomavirus (HPV) infection in the Mexican population. We studied 356 paraffin-embedded tissues from unrelated Mexican men with PCa or benign prostatic hyperplasia (BPH), with the latter serving as control. HPV detection was performed by polymerase chain reaction (PCR) using universal primers, and viral genotypes were detected using sequencing or multiplex PCR. Light microscopy analyses enabled the identification of koilocytes in samples subsequently analyzed for HPV detection by in situ PCR and for p16-INK4A expression by immunohistochemistry. The results showed that high risk- (HR) HPVs were detected in 37/189 (19.6%) PCa specimens compared to 16/167 (9.6%) of BHP specimens (odds ratio 2.3; 95% CI= 1.2 to 4.3; p=0.01). These data suggest HR-HPV may play a role in PCa. HPV 52 and 58 were the most frequent genotypes (33 and 17%, respectively) detected in the population studied. Koilocytes were detected in all in situ PCR-HPV-positive samples, representing a pathognomonic feature of infection, and we observed the overexpression of p16-INK4A in HPV-positive samples compared to HPV-negative samples, indirectly suggesting the presence of HR-HPV E7 oncoprotein. These results suggest that HPV infection plays an important role in prostate cancer development.

Association between Human Papillomavirus and Non-cervical Genital Cancers in Brazil: A Systematic Review and Meta-Analysis

Background: Human papillomavirus (HPV) infection is associated with cervical cancer; however, it is controversial whether it is involved in non-cervical genital cancers. Objective: This study aimed to evaluate articles on the prevalence of HPV in penile cancer, vulvar cancer, colorectal cancer, prostate cancer and anal canal cancer in studies conducted in Brazil. Methods: The study was conducted in accordance with the Preferred Reporting of Systematic Reviews and Meta-Analysis Statement. Comprehensive searches for HPV and cancer for the years 2006 to 2016 were conducted in two databases (PubMed and Web of Knowledge) and Google Scholar system. We also tracked the references of all eligible articles to identify additional non-captured publications through online surveys. Results: Eighteen studies, with a combined sample size of 1,552 patients were analyzed. The overall prevalence of HPV was 43% (95% CI: 36–51%; p < 0.001). The pooled prevalence of HPV in penile cancer was 42% (95% CI: 32–55%; p < 0.001), in colorectal cancer it was 67% (95% CI: 64–70%; p < 0.001) and in vulvar cancer 43% (95% CI: 34–55%; p < 0.001). HPV 16 was the most prevalent in all sites evaluated, with prevalence estimated at 54% (95% CI: 44–66%; p < 0.001), followed by genotypes 33 (21%; 95% CI: 17–28; p < 0.001), 6 (15%; 95% CI: 8–26%; p < 0.001), 11 (13%; 95% CI: 5–32%; p < 0.001) and 18 (12%; 95% CI: 7–22%; p < 0.001), respectively. The pooled prevalence of single infection was 82% and infection by multiple genotypes of HPV was 22%. Conclusion: Our study demonstrated a high prevalence of HPV in non-cervical genital cancers in Brazil, with predominance of genotype 16, providing evidence for the need for preventive and control measures to avoid future harm to the population.

Human papilloma virus and genitourinary cancers: a narrative review

INTRODUCTION

Human papilloma virus (HPV) is the most common sexually transmitted pathogen and its potential role in the genesis of several diseases such as cervical, head and neck, anal and penile cancers, is now largely recognized. Aim of this review article was to evaluate and summarize the state of the art of HPV-related urogenital cancers, focusing on the potentially innovative methods for the diagnosis of infection that should be used to improve viral causative detection and prevent its diffusion through sexual intercourses.

EVIDENCE ACQUISITION

The initial search was carried out by using the Medline and the Google Scholar computerized databases through the selected key-words to identify the more recent literature on HPV epidemiology and its relationship with the main relevant urinary tract cancers. Studies were selected, extracted, analyzed and summarized. The PRISMA statement criteria were adopted and reported.

EVIDENCE SYNTHESIS

Polymerase chain reaction assay (HPV test) represents the best option for the diagnosis of HPV infection. Difficulties for the diagnosis in male are due to the site of investigation (glans, sub coronal sulcus, scrotum, urine, sperm) and the method adopted to take the sample (brushing, tissue biopsy). Due to these reasons several studies analyzed seemed to be incomparable. HPV infection is generally found in about 20% of heterosexual men. Its connection with cervical, anal, head and neck and penile cancer has been previously evidenced in 90%, 60%, 68% and 40% of cases respectively. In particular, HPV infection differed significantly among penile squamous cell carcinoma (SCC) subtypes ranging from 22.4% in verrucous subtype to 66.3% for the basaloid/warty subtype. Although the connection between prostate cancer and HPV infection has never been previously confirmed, forest plot analysis relative to a series of nine studies done during the last ten years, demonstrated a 7.7 objective risk (OR) for subjects with HPV infection to develop subsequent prostate cancer. On the other hand, some authors found comparable results in subjects with prostate cancer, benign prostate hyperplasia and prostate inflammation, thus demonstrating that this link still remains questionable. Similarly, the connection between HPV infection and urothelial, testicular and renal cancer continue to be hotly debated although HPV has been found in the urine, semen and renal tissue of patients respectively.

CONCLUSIONS

Integrated parts of HPV (E6 and E7 fractions) have been previously found in cervical, head and neck, anal and penile cancers. Conversely, although the evidence of concomitant HPV infection, integrated viral genome in cancer cells DNA had never been demonstrated in all the other genito-urinary tract cancers, and its role in the tumor genesis remain still largely debated. This is the reason why HPV infection should be tested in all patients with genitourinary cancer to better investigate about its potential role in the tumor genesis and development. Moreover, HPV infection option should be kept in mind when considering possible viral transmission to sexual partners.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The high-risk HPV infection and urinary system tumor

HPV is classified into high-risk and low-risk types depending on its probability of leading to tumorigenesis. Many studies have shown that HPV infection, especially the infection caused by the high-risk type, is always related to prostate cancer, bladder cancer, penile cancer, testicular cancer, and other urinary system tumors. However, previous studies differed in sexual openness and racial genetic susceptibility of the study object, sample size, and experimental methods. Hence, the correlation between high-risk HPV infection and urinary system tumors remains controversial. The early open reading frame of the HPV genome is composed of E1–E7, among which E6 and E7 are the key transfer proteins. The combination of these proteins with oncogene and anti-oncogene may be one of the mechanisms leading to tumorigenesis.

Integrity of a HPV11 infection cell model and identification of (-)-Epigallocatechin-3-gallate as a potential HPV11 inhibitor

Background

Condyloma acuminatum (CA) is one of the most common sexually transmitted diseases and induced by low-risk human papillomaviruses (HPVs), mainly HPV type 6 and 11. Here, we report the identification of (-)-Epigallocatechin-3-gallate (EGCG) by an HPV11 infection cell model.

Results

The recombined HPV11.HaCaT cells had stable HPV 11 early genes expression. The introducing of HPV11 genome significantly increased the proliferation of HPV11.HaCaT cells, as well as the proportion of cells in S and G2/M phases. After treated with rhIFN-α 2a, IFN signaling pathway was activated in both HaCaT and HPV11.HaCaT cells, while HPV11 decreased the activation level. In addition, rhIFN-α 2a, could inhibit expression of HPV 11 E6 and E7 mRNA significantly (P<0.05). However, cell growth and cell cycle did not show statistical difference (P>0.05). Nevertheless, EGCG, a major active constituent in tea polyphenol, showed strong anti-HPV11 effect, which inhibited HPV11 E6 and E7 mRNA.

Methods

Gene transfection technique was used to introduce HPV11 genome into HaCaT cells, named HPV11.HaCaT cells. With the established cell model, we explore the anti-HPV11 effect of (-)-Epigallocatechin-3-gallate (EGCG) on cell growth, viability and affection on expression HPV11 E6 and E7 mRNA.

Conclusion

Our data collectively demonstrated that the recombinant HPV11.HaCaT cells were integral and practical to be a cell model to test anti-HPV11 agents and explore the interaction between HPV11 genes and host cells. And EGCG inhibits expression of HPV11 E6 and E7 mRNA in the recombinant HPV11.HaCaT cells.

A systematic review on multiparametric MR imaging in prostate cancer detection

BACKGROUND

Literature data suggest that multi-parametric Magnetic Resonance Imaging (MRI), including morphologic T2-weigthed images (T2-MRI) and functional approaches such as Dynamic Contrast Enhanced-MRI (DCE-MRI), Diffusion Weighted Imaging (DWI) and Magnetic Resonance Spectroscopic Imaging (MRSI), give an added value in the prostate cancer localization and local staging.

METHODS

We performed a systematic review of literature about the role and the potentiality of morphological and functional MRI in prostate cancer, also in a multimodal / multiparametric approach, and we reported the diagnostic accuracy results for different imaging modalities and for different MR coil settings: endorectal coil (ERC) and phased array coil (PAC). Forest plots and receiver operating characteristic curves were performed. Risk of bias and the applicability at study level were calculated.

RESULTS

Thirty three papers were identified for the systematic review. Sensitivity and specificity values were, respectively, for T2-MRI of 75% and of 60%, for DCE-MRI of 80% and of 72%, for MRSI of 89% and of 69%, for combined T2-MRI and DCE-MRI of 87% and of 46%, for combined T2-MRI and MRSI of 79% and of 57%, for combined T2-MRI, DWI and DCE-MRI of 81% and of 84%, and for combined MRSI and DCE-MRI of 83% and of 83%. For MRI studies performed with ERC we obtained a pooled sensitivity and specificity of 81% and of 66% while the pooled values for MRI studies performed with PAC were of 78% and of 64%, respectively (p>0.05 at McNemar test). No studies were excluded from the analysis based on the quality assessment.

CONCLUSIONS

ERC use yielded no additional benefit in terms of prostate cancer detection accuracy compared to multi-channel PAC use (71% versus 68%) while the use of additional functional imaging techniques (DCE-MRI, DWI and MRSI) in a multiparametric MRI protocol improves the accuracy of prostate cancer detection allowing both the early cure and the guidance of biopsy.

High risk human papilloma viruses (HPVs) are present in benign prostate tissues before development of HPV associated prostate cancer

Background

Although high risk HPVs are associated with an increased risk of prostate cancer it is not known if they have a causal role. The purpose of this study is to investigate the potential role of human papilloma viruses (HPVs) in prostate cancer. The aims are (i) to investigate the presence and confirm the identity of high risk HPVs in benign prostate tissues prior to the development of HPV positive prostate cancer in the same patients, and (ii) to determine if HPVs are biologically active.

Methods

We used polymerase chain reaction (PCR) to identify HPVs in specimens from 52 Australian men with benign prostate biopsies who 1 to 10 years later developed prostate cancer. Immunohistochemistry (IHC) was used to assess the expression of HPV E7 oncoproteins, cytokeratin and prostate specific antigen (PSA).

We used RNASeq data from The Cancer Genome Atlas (TCGA) to identify possible HPV RNA sequences in prostate cancer.

Results

HPV screening using standard PCR was conducted on 28 of the 52 sets of benign and later prostate cancers. HPV L1 genes were identified in 13 (46%) benign and 8 (29%) of 28 later prostate cancers in the same patients. HPV E7 genes were identified in 23 (82%) benign and 19 (68%) of 28 subsequent prostate cancers in the same patients. The same HPV types were present in both the benign and subsequent prostate cancers in 9 sets of specimens. HPV type 16 was identified in 15% of benign and 3% of prostate cancers. HPV type 18 was identified in 26% of benign and 16% of prostate cancers. Small numbers of HPV types 45, 47, 76 and 115 were also identified.

High confidence RNA-Seq evidence for high risk HPV types 16 and 18 was identified in 12 (2%) of the 502 TCGA prostate cancer transcriptomes.

High risk HPV E7 oncoprotein was positively expressed in 23 (82%) of 28 benign prostate specimens but only in 8 (29%) of 28 of the later prostate cancer specimens. This difference is statistically significant (p = 0.001). Prostate specific antigen (PSA) was more highly expressed in 26 (50%) of 52 prostate cancer specimens as compared to prior benign prostate specimens in the same patients.

Conclusions

High risk HPVs are present in benign prostate tissues prior to the development of HPV positive prostate cancer. There is a significantly higher expression of HPV E7 oncoproteins in benign prostate tissues as compared to late prostate cancer that subsequently developed in the same patients. This observation suggests that HPV oncogenic activity is an early phenomenon in a majority of prostate oncogenesis. TCGA RNA-Seq data suggests that HPV is biologically active in some prostate tumour samples.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-017-0157-2) contains supplementary material, which is available to authorized users.

Association between human papillomavirus and prostate cancer: A meta-analysis

Observational studies have suggested an association between human papillomavirus (HPV) infection and the risk of prostate cancer (PCa). However, the association between HPV infection and the risk of PCa remains unclear. The aim of the present meta-analysis study was to investigate whether HPV serves a role in increasing the risk of PCa. Relevant previous studies up to May 2015 were searched in PubMed, Web of Science, Cochrane library, Chinese National Knowledge Infrastructure, China Wan Fang database and China Biomedical Literature Database. A random-effects model or fixed-effects model was employed to determine odds ratios (ORs) with 95% confidence intervals (CIs), when appropriate. Heterogeneity was evaluated using Q and I2 statistical analysis. A total of 24 case-control studies involving 971 patients and 1,085 controls were investigated to estimate the association between HPV infection and PCa risk. The pooled estimate for OR was 2.27 (95% CI, 1.40-3.69). Stratified pooled analyses were subsequently performed according to the HPV detection methods, geographical regions, publication years and types of tissue. Sensitivity analysis based on various exclusion criteria maintained the significance with respect to PCa individually. Little evidence of publication bias was observed. The meta-analysis suggested that HPV infection is associated with increasing risk of PCa, which indicated a potential pathogenetic link between HPV and PCa.

Dietary intakes of citrus fruit and risk of gastric cancer incidence: an adaptive meta-analysis of cohort studies

OBJECTIVES:

In the context of supplementary antioxidants having no anticancer effect, it is important to update the meta-analysis to evaluate whether there is an association between intake of citrus fruit and gastric cancer risk.

METHODS:

The list of articles to be searched was established using citation discovery tools provided by PubMed and Scopus. The effect size of each article to be used in meta-analysis was calculated using the interval-collapse method. Summary effect size (sES) and 95% confidence intervals (CI) were obtained by conducting this meta-analysis. Random effect dose–response meta-regression (DRMR) was performed to investigate the dose–response relationship.

RESULTS:

A total of five cohort studies were selected. The result was 13% reduction of gastric cancer according to the intake of citrus fruit (sES, 0.87; 95% CI, 0.76 to 0.99; I-squared=69.6%). In subgroup analysis, it was found that the intake of citrus fruit inhibited cardia gastric cancer (CGC) (sES, 0.67; 95% CI, 0.55 to 0.81; I-squared=46.1%) and as a result of DRMR, 100 g of citrus fruit intake per day inhibits CGC by 40% (relative risk, 0.60; 95% CI, 0.44 to 0.83).

CONCLUSIONS:

It is suggested that the intake of citrus fruit inhibits the development of CGC. This conclusion can be used as a primary prevention measure in the future when the incidence of CGC may be on the rise.

Human papillomavirus infection and risk of breast cancer: a meta-analysis of case-control studies

Background

Although systematic reviews (SR) report that human papillomavirus (HPV) increases the risk of breast cancer, there are still disputes regarding this association. In particular, it has been argued that the risk level differs depending on nationality, type of tissue, subtype of HPV, and publication year. Considering that the searching year of publication for the previous SRs was June 2013, a renewal meta-analysis needs to be conducted.

Methods

Using articles selected in the previous SRs, we compiled a list of references, cited articles, and related articles from the PubMed and Scopus databases. Of these, only publications with data from case-control studies on HPV DNA-positivity in tissues were chosen. Summary odds ratio (SOR) and 95 % confidence interval (CI) were calculated through meta-analysis. Meta-regression analysis was performed for nationality, types of tissue, subtype of HPV, and publication year.

Results

Twenty-two case-control studies were selected, and the total number of individuals in the case and control group was 1897 and 948, respectively. According to the meta-analysis about the 22 publications, HPV infection increased the risk of breast cancer (SOR = 4.02, 95 % CI: 2.42–6.68; I-squared = 44.7 %). Statistical significance was not found in meta-regression performed on the four variables of nationality, type of tissue, subtype of HPV, and publication year which some researchers think sources of heterogeneity.

Conclusions

The results of the present study supported the argument that HPV infection increases the risk of breast cancer. Age-matched case-control studies are in need in the future.

Epstein-Barr Virus and Gastric Cancer Risk: A Meta-analysis With Meta-regression of Case-control Studies

Objectives:

Research on how the risk of gastric cancer increases with Epstein-Barr virus (EBV) infection is lacking. In a systematic review that investigated studies published until September 2014, the authors did not calculate the summary odds ratio (SOR) due to heterogeneity across studies. Therefore, we include here additional studies published until October 2015 and conduct a meta-analysis with meta-regression that controls for the heterogeneity among studies.

Methods:

Using the studies selected in the previously published systematic review, we formulated lists of references, cited articles, and related articles provided by PubMed. From the lists, only case-control studies that detected EBV in tissue samples were selected. In order to control for the heterogeneity among studies, subgroup analysis and meta-regression were performed.

Results:

In the 33 case-control results with adjacent non-cancer tissue, the total number of test samples in the case and control groups was 5280 and 4962, respectively. In the 14 case-control results with normal tissue, the total number of test samples in case and control groups was 1393 and 945, respectively. Upon meta-regression, the type of control tissue was found to be a statistically significant variable with regard to heterogeneity. When the control tissue was normal tissue of healthy individuals, the SOR was 3.41 (95% CI, 1.78 to 6.51; I-squared, 65.5%).

Conclusions:

The results of the present study support the argument that EBV infection increases the risk of gastric cancer. In the future, age-matched and sex-matched case-control studies should be conducted.

Citation Discovery Tools for Conducting Adaptive Meta-analyses to Update Systematic Reviews

OBJECTIVES

The systematic review (SR) is a research methodology that aims to synthesize related evidence. Updating previously conducted SRs is necessary when new evidence has been produced, but no consensus has yet emerged on the appropriate update methodology. The authors have developed a new SR update method called 'adaptive meta-analysis' (AMA) using the 'cited by', 'similar articles', and 'related articles' citation discovery tools in the PubMed and Scopus databases. This study evaluates the usefulness of these citation discovery tools for updating SRs.

METHODS

Lists were constructed by applying the citation discovery tools in the two databases to the articles analyzed by a published SR. The degree of overlap between the lists and distribution of excluded results were evaluated.

RESULTS

The articles ultimately selected for the SR update meta-analysis were found in the lists obtained from the 'cited by' and 'similar' tools in PubMed. Most of the selected articles appeared in both the 'cited by' lists in Scopus and PubMed. The Scopus 'related' tool did not identify the appropriate articles.

CONCLUSIONS

The AMA, which involves using both citation discovery tools in PubMed, and optionally, the 'related' tool in Scopus, was found to be useful for updating an SR.

Human papillomavirus infection and risk of lung cancer in never-smokers and women: an 'adaptive' meta-analysis

OBJECTIVES:

The incidence of lung cancer in Koreans is increasing in women and in both men and women with a never-smoking history. Human papillomavirus (HPV) infection has been suggested as a modifiable risk factor of lung cancer in never-smokers and women (LCNSW). This systematic review (SR) aimed to evaluate an association between HPV infection and lung cancer risk in LCNSW.

METHODS:

Based on a prior SR and some expert reviews, we identified refereed, cited, or related articles using the PubMed and Scopus databases. All case-control studies that reported the odds ratio of HPV infection in LCNSW were selected. An estimate of the summary odds ratio (SOR) with 95% confidence intervals (CI) was calculated.

RESULTS:

A total of four case-control studies were included. The fixed-effect model was applied because of homogeneity (I-squared=0.0%). The SORs in women and in never-smokers were 5.32 (95% CI, 1.75 to 16.17) and 4.78 (2.25 to 10.15) respectively.

CONCLUSIONS:

These results showed a significant effect of HPV infection in LCNSW. It is evident that developing a preventive plan against LCNSW may be necessary.

Hormonal Replacement Therapy and the Risk of Lung Cancer in Women: An Adaptive Meta-analysis of Cohort Studies

Objectives:

Approximately 10% to 15% of lung cancer cases occur in never-smokers. Hormonal factors have been suggested to lead to an elevated risk of lung cancer in women. This systematic review (SR) aimed to investigate the association between hormonal replacement therapy (HRT) and the risk of lung cancer in women using cohort studies.

Methods:

We first obtained previous SR articles on this topic. Based on these studies we made a list of refereed, cited, and related articles using the PubMed and Scopus databases. All cohort studies that evaluated the relative risk of HRT exposure on lung cancer occurrence in women were selected. Estimate of summary effect size (sES) with 95% confidence intervals (CIs) were calculated.

Results:

A total of 14 cohort studies were finally selected. A random effect model was applied due to heterogeneity (I-squared, 64.3%). The sES of the 14 articles evaluating the impact of HRT exposure on lung cancer occurrence in women indicated no statistically significant increase in lung cancer risk (sES, 0.99; 95% CI, 0.90 to 1.09).

Conclusions:

These results showed that HRT history had no effect on the risk of lung cancer in women, even though the sES of case-control studies described in previous SR articles indicated that HRT had a protective effect against lung cancer. It is necessary to conduct a pooled analysis of cohort studies.

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.

Hormone Replacement Therapy and Risk of Breast Cancer in Korean Women: A Quantitative Systematic Review

Objectives:

The epidemiological characteristics of breast cancer incidence by age group in Korean women are unique. This systematic review aimed to investigate the association between hormone replacement therapy (HRT) and breast cancer risk in Korean women.

Methods:

We searched electronic databases such as KoreaMed, KMbase, KISS, and RISS4U as well as PubMed for publications on Korean breast cancer patients. We also conducted manual searching based on references and citations in potential papers. All of the analytically epidemiologic studies that obtained individual data on HRT exposure and breast cancer occurrence in Korean women were selected. We restricted the inclusion of case-control studies to those that included age-matched controls. Estimates of summary odds ratio (SOR) with 95% confidence intervals (CIs) were calculated using random effect models.

Results:

One cohort and five case-control studies were finally selected. Based on the heterogeneity that existed among the six studies (I-squared=70.2%), a random effect model was applied. The summary effect size of HRT history from the six articles indicated no statistical significance in breast cancer risk (SOR, 0.983; 95% CI, 0.620 to 1.556).

Conclusions:

These facts support no significant effect of HRT history in the risk of breast cancer in Korean women. It is necessary to conduct a pooled analysis.

The necessity of an observational study on the interactions between allergic history and citrus fruit intake for the prevention of pancreatic cancer

While the main product of Jeju Island is citrus fruit and the prevalence of atopic dermatitis among the students who live there is relatively high, the incidence of pancreatic cancer is lowest in Korea. Systematic reviews reporting allergic history and intake of citrus fruit as protective factors against pancreatic cancer (PCC) were published in 2005 and 2008, respectively. Although there were discrepancies in the results of the subgroup analyses between case-control and cohort studies, it is necessary to evaluate an interaction effect between allergic history and intake of citrus fruits on PCC risk.