Enhanced oncogenicity of human papillomavirus type 16 (HPV16) variants in Japanese population

To investigate whether HPV16 E6 variants carry an elevated risk for cervical cancer in Japanese population, we investigated the E6 sequence variation in 40 cervical intraepithelial neoplasias (CINs) I-III and 43 invasive cervical cancers (ICCs), all positive for HPV16. HPV16 E6 variants were frequently found in ICCs than in CINs (88 vs. 65%, P=0.01). The E6 D25E, a rare variant in Western countries, was most frequently observed in ICC (44%). CIN I/II lesions with HPV16 variants were less likely to regress than those with HPV16 prototype (P=0.048). The finding that HPV16 E6 variants represent a significant risk factor is common between Western and Japanese women despite the different distribution of each variant.