Targeting of transcriptional cofactors by the HPV E6 protein: another tale of David and Goliath

The probability of involvement of human papillomavirus in the carcinogenesis of bladder small cell carcinoma, prostatic ductal adenocarcinoma, and penile squamous cell carcinoma: a case report

Background

Human papillomavirus is associated with urogenital carcinogenesis such as penile and uterine cervix cancer. On the other hand, association between human papillomavirus infection and risk of bladder and prostatic cancer remains controversial.

Case presentation

We report a rare case of a 67-year-old Japanese man with synchronous triple urogenital cancer including bladder small cell carcinoma, prostatic ductal adenocarcinoma, and penile squamous cell carcinoma, who presented with a history of asymptomatic gross hematuria. Bladder small cell carcinoma and prostatic ductal adenocarcinoma were diagnosed by histopathological examination after transurethral resection of the tumor. Moreover, he was diagnosed with penile carcinoma based on the exfoliative cytodiagnosis of nodular and papillary tumors inside the preputial collar. He was treated with laparoscopic radical cystectomy, urethrectomy, partial penectomy with pelvic lymph node dissection, and ileal conduit urinary diversion.

To identify a common pathogenesis, we considered human papillomavirus as an etiologic factor because it is a known risk factor for penile carcinoma. Human papillomavirus deoxyribonucleic acid bands were detected by polymerase chain reaction in the three tumors. There was a possibility that human papillomavirus was involved in the carcinogenesis of the triple cancer.

Conclusions

To the best of our knowledge, this is the first report of the synchronous triple urogenital cancer of small cell carcinoma of the bladder, ductal adenocarcinoma of the prostate and penile squamous cell carcinoma. We believe that human papillomavirus may have been involved in the carcinogenesis of the triple urogenital cancer described in this case.

Molecular interactions of 'high risk' human papillomaviruses E6 and E7 oncoproteins: implications for tumour progression

The aetiology of cervical cancer has been primarily attributed to human papillomaviruses (HPVs). These are characterized by the persistent expression of the two oncogenes, E6 and E7. Experimental studies show that E6 and E7 genes of the high risk HPVs deregulate key cell cycle controls. Recent work has uncovered new cellular partners for these proteins that throw light on many of the pathways and processes in which these viral proteins intervene. This review focuses on the regulation of host proteins by the viral oncoproteins and consequence of such interactions on cell survival, proliferation, differentiation and apoptosis.

Viral replication and the coactivators p300 and CBP

Productive viral infection requires coordinate regulation of viral and cellular gene expression. Viruses of different classes have evolved different mechanisms to conform to, adapt to and exploit programs of cellular gene expression. Many viral gene products influence and respond to cellular signals that control differentiation and proliferation Transcriptional coactivators are central to the regulation of the expression of genes controlling these events. p300 and CBP are closely related coactivators that regulate the transcription of specific genes, modify chromatin structure and influence cell cycle progression. In this review, the different molecular interactions of proteins encoded by DNA tumor viruses and lentiviruses with these transcriptional coactivators and related cellular proteins are summarized.