HPV16 induces penile intraepithelial neoplasia and squamous cell carcinoma in transgenic mice: first mouse model for HPV-related penile cancer.

Penile cancer is an under-studied disease that occurs more commonly in developing countries and 30-50% of cases show high-risk human papillomavirus (HPV) infection. Therapeutic advances are slow, largely due to the absence of animal models for translational research. Here, we report the first mouse model for HPV-related penile cancer. Ten-week-old mice expressing all the HPV16 early genes under control of the cytokeratin 14 (Krt14) gene promoter and matched wild-type controls were exposed topically to dimethylbenz(a)anthracene (DMBA) or vehicle for 16 weeks. At 30 weeks of age, mice were sacrificed for histological analysis. Expression of Ki67, cytokeratin 14, and of the HPV16 oncogenes E6 and E7 was confirmed using immunohistochemistry and quantitative PCR, respectively. HPV16-transgenic mice developed intraepithelial lesions including condylomas and penile intraepithelial neoplasia (PeIN). Lesions expressed cytokeratin 14 and the HPV16 oncogenes E6 and E7 and showed deregulated cell proliferation, demonstrated by Ki67-positive supra-basal cells. HPV16-transgenic mice exposed to DMBA showed increased PeIN incidence and squamous cell carcinoma. Malignant lesions showed varied histological features closely resembling those of HPV-associated human penile cancers. Wild-type mice showed no malignant or pre-malignant lesions even when exposed to DMBA. These observations provide the first experimental evidence to support the etiological role of HPV16 in penile carcinogenesis. Importantly, this is the first mouse model to recapitulate key steps of HPV-related penile carcinogenesis and to reproduce morphological and molecular features of human penile cancer, providing a unique in vivo tool for studying its biology and advancing basic and translational research. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.