The cigarette smoke carcinogen benzo[a]pyrene enhances human papillomavirus synthesis

Epidemiological studies suggest that cigarette smoke carcinogens are cofactors which synergize with human papillomavirus (HPV) to increase the risk of cervical cancer progression. Benzo[a]pyrene (BaP), a major carcinogen in cigarette smoke, is detected in the cervical mucus and may interact with HPV. Exposure of cervical cells to high concentrations of BaP resulted in a 10-fold increase in HPV type 31 (HPV31) viral titers, whereas treatment with low concentrations of BaP resulted in an increased number of HPV genome copies but not an increase in virion morphogenesis. BaP exposure also increased HPV16 and HPV18 viral titers. Overall, BaP modulation of the HPV life cycle could potentially enhance viral persistence, host tissue carcinogenesis, and permissiveness for cancer progression.