In a recent Scientific Reports study, scientists conducted a meta-analysis to look at the role of human papillomavirus (HPV) in prostate carcinogenesis.

Study: Human papillomavirus and prostate cancer: Systematic review and meta-analysis. Image Credit: Corona Borealis Studio / Shutterstock.com

The epidemiology of prostate cancer

Prostate cancer is a major health problem and the fifth leading reason behind death in men worldwide. The prevalence of prostate cancer varies across different regions, with the very best prevalence reported in Northern and Western Europe, North America, South Africa, Australia/Recent Zealand, and the Caribbean, whereas the bottom incidence of prostate cancer has been recorded in Asia and North Africa. This variability within the incidence rate of prostate cancer has been attributed to different socioeconomic status and health policies of other countries. 

Some risk aspects related to prostate cancer include age, genetic predisposition, and family history. Previously, researchers have reported that HOXB13 mutation increases the danger of prostate cancer. Other genes related to prostate cancer include BRCA1, BRCA2, and the MSH2 gene.

Ethnicity also plays a distinguished role within the manifestation of prostate cancer. In comparison with Asian men, for instance, black men in the US and the Caribbean have the very best rate of prostate cancer.

HPV and cancer

About 15% of all human cancers are related to viruses. Some viruses can modify the behavior of tumor cells by blocking apoptosis pathways, triggering angiogenesis, inhibiting tumor suppressor signaling, and promoting metastasis.

Although HPV is related to cervical cancer in women, it doesn’t appear to extend the danger of ovarian and endometrial cancer.

A previous study has indicated that HPV infection influences prostate cancer pathogenesis. Likewise, genetic and clinical studies have indicated a potentially causal relationship between HPV and prostate cancer.

This remark was based on identifying HPV-associated koilocytes in prostate cancer samples. A better expression of HPV E7 oncoproteins was also present in benign prostate tissues in comparison with advanced prostate cancer.

Nevertheless, some studies have contradicted the concept of HPV being related to the incidence of prostate cancer. Thus, the precise role of HPV in prostate cancer incidence is unclear. 

Concerning the study

The present meta-analysis obtained all relevant studies from publicly available bibliometric databases, including Embase, PubMed, Medline, and Scopus, from their inception to August 21, 2022. The study considered research with morphologically confirmed prostate cancer diagnosis and HPV presence by polymerase chain response (PCR) assay.

HPV infection increases the danger of prostate cancer as in comparison with normal tissues, not BPH

The initial search resulted in a complete of 271 articles. After removing duplicates and considering all eligibility criteria, 27 case-control studies were considered.

These studies included analyses of 1,607 prostate tumor tissue samples and 1,443 control samples. The tumor prostrate sample was considered the study sample, whereas normal prostate and benign prostatic hyperplasia (BPH) tissues were considered the control.

The link between the danger of prostate cancer and HPV infection is important when normal prostate tissue is taken into account the control. Comparatively, when BPH was considered a control, this association was not statistically significant. This finding revealed that the variety of control tissue impacts the association between HPV infection and prostate cancer risk.

In 1990, the presence of HPV types 16 and 18 was first detected in prostate cancer tissues. This study highlighted that standard prostate tissue or BPH as a control impacted the study end result.

BPH samples have a quantitative advantage in comparison with normal tissue, as HPV detection frequency in BPH is higher. Subsequently, no significant association between HPV infection and BPH was present in these studies.

HPV infection is a “hit and run” phenomenon, through which an entire or incomplete viral genome is detected only within the early stage of prostate cancer. It becomes undetectable within the later stage of cancer. High-risk HPV types 16 and 18 are commonly present in BPH tissues for one to 10 years before developing HPV-positive prostate cancer. 

Along with detecting the presence of HPV, it is crucial to find out the physical status of the HPV genome in HPV-positive samples. During carcinogenesis, HPV DNA is present in an integrated form characterised by overexpression of E6 and E7 genes. HPV infection could also aid in increasing the resistance to apoptosis in human prostate tumor cells.

Conclusions

The present study indicated that HPV infection increases men’s prostate cancer risk. In the long run, more research is required to elucidate the precise role of HPV in the event of prostate cancer, through which normal prostate tissues, quite than BPH samples, function control.