Human papillomaviruses target differentiating epithelia for virion production and malignant conversion

Human papillomaviruses infect stratified epithelial cells and induce hyperproliferative lesions. Over 70 different HPV types have been identified and each targets epithelia at distinct body locations. A subset, including HPV types 16, 18, 31, 45 and 54, target the genital tract and are the etiological agents of cervical cancers. While viral infection is a necessary prerequisite for the development of most cervical cancers, it is not by itself sufficient indicating that secondary; mutational events are also required. The viral life is closely linked to epithelial differentiation and this process is disrupted in the development of malignancies. In a productive infection, vegetative replication and production of virions is restricted to highly differentiated suprabasal cells. Analysis of the mechanisms regulating the viral life cycle in differentiating epithelia provides insight into why certain types induce cancers of the genital tract.