Human papillomaviruses: a growing field.

A combination of functional studies on human papillomavirus (HPV) oncoproteins and epidemiological studies on persistence of HPV infection firmly established a role for HPV in the etiology of cervical cancers. Understanding the viral life cycle of HPVs has been more difficult. In this issue of Genes & Development, Wang et al. (pp. 181 - 194) describe an efficient method to propagate infectious HPV in differentiating epithelium, providing clear evidence for temporal separation of viral and cellular replication.