Human papillomavirus (HPV) is the necessary but probably not sufficient cause of cervical precancer and
cancer. Secondary exogenous and endogenous factors, HPV cofactors, may contribute to the probability of a
cancer-associated (oncogenic)
HPV infection progressing to cervical precancer and
cancer. For these cofactors to influence the natural history of
HPV infection, they must act on cervical tissue to promote viral persistence, progression to precancer or
cancer given viral persistence, or both. The aim of this review was to examine briefly the impact these factors may have on
carcinogenesis of the cervix. Specifically, the roles of the cervical transformation zone, cervical immunity,
inflammation and
coinfection, and exposure to the main HPV cofactors (smoking,
oral contraceptive use, and multiparity) are discussed.