Association of high-risk human papillomavirus with prostate and bladder cancers: a UK based population study

Human papillomavirus (HPV) infection is one of the sexually transmitted diseases
which have been implicated in the aetiology of multiple cancers. To date, several
studies have been conducted to evaluate the incidence of high-risk (HR) HPV in
prostate and bladder cancers which have generated widely conflicting data. Hence,
this leaves a lack of awareness on the causal role of persistent HPV infection in the
development of these cancers. Although this has been investigated in a handful of
countries, to the best of our knowledge, no prior studies have been conducted in the
UK. Hence this study aimed to investigate the presence and expression of HR-HPV
types in 49 fresh prostate specimens (35 benign and 14 malignant specimens) and 55
bladder specimens (4 benign and 51 malignant) using DNA PCR and Sanger
Sequencing. Data obtained confirmed the presence of HR-HPVs in 16/49 (32.7%) of
analysed benign and malignant prostate tissues with HPV35 being identified as the
most frequent type. Moreover, HR-HPV positivity rate was found to be higher in
abnormal prostate tissues (adenocarcinoma and benign with prostatitis) compared
those with normal prostate condition. Results obtained from bladder samples
confirmed the presence of HR-HPVs in 17/55 (31%), bladder samples with HPV16,
HPV35 and HPV52 as the most prevalent type. Interestingly, HPV18 was not detected
in any samples (prostate and bladder) analysed. Using immunohistochemistry, this
study has confirmed the expression of HPV protein in all prostate tissues positive for
HPV DNA and 82% of HPV positive bladder samples.

In this study we had a patient with both bladder and prostate cancers and have
investigated the presence and expression of HR HPV types in samples collected from
both organs. Interestingly, data obtained shows the presence and expression of the
same HPV types (HPV35, HPV45 and HPV59) in both organs. This notable finding
suggests that HPV can not only be transmitted from one person to other person (via
skin-to-skin contact) it can also be transported from one internal organ to the other
organ and help cancer to metastasise elsewhere. Finally, to examine the mechanism of
action by which HPV can affect the host genome RNA sequencing was carried out on
few bladder samples positive for HPV and a sample negative for HPV. Data obtained
from this experiment revealed the overexpression of genomes related to mitochondrial
function in HPV positive bladder cancers, which may help cellular respiration of
cancer cells.

In conclusion, these findings, the first to report in the UK, suggest that the presence
and expression of HR-HPV types in prostate and bladder tissue is likely to be a related
factor in the progression of certain cases of prostate and bladder cancer.