Pathogenic Contribution of Human Papillomaviruses and Epstein–Barr Virus to Prostate Cancer in Bulgarian Patients

Abstract

We investigate the prevalence and impact of Human Papillomaviruses (HPVs) and Epstein–Barr Virus (EBV) and other human herpesviruses (HHVs) in Formalin-fixed paraffin-embedded (FFPE) prostate cancer (PCa) samples (n = 49) and benign prostatic hyperplasia (BPH) controls (n = 50) from Bulgarian patients. DNA/RNA extraction, multiplex PCR, Real-time qPCR, ISH were applied.

EBV DNA was detected in 34.7% of PCa samples and 6% of BPH controls (p = 0.0048, Fisher's exact test – FET), suggesting a significant association with malignancy. Among EBV-positive PCa cases, 58% represented mono-infection, while 41.2% involved co-infections with other HHVs. The high prevalence of EBV supports its potential role in PCa development via inflammation and immune modulation. The immunological profile based on IL1β, IL10, IL18, TNF-α, TLR4, GATA3, CD68-expression, revealed an inflammatory tumour microenvironment in EBV/HHVs positive PCa. Notably the majority of samples were classified as Gleason grades G3–G5, consistent with tumour aggressiveness and poor prognosis.

HPV DNA was detected in 6.1% of PCa and 12% of BPH samples, showing no statistically significant difference (p = 0.327, FET). The lack of HPV association in PCa/BPH groups suggests a limited role in advanced disease. These results combined with the absence of hrHPV E6/E7 RNA supports the “hit and run” model, in which HPV contributes to early tumour initiation but is often absent in later stages.

Our findings suggest that long-term EBV/HHVs infection may contribute to immune dysregulation in the prostate and may serve as a predictor of aggressive PCa.