Sequence variations of the late upstream region of HPV16 in cervical intraepithelial neoplasm and invasive carcinoma.

Abstract

HPV16 is the most common type of human papillomavirus (HPV) seen in cervical squamous cell carcinoma. A 78-bp promotor element at nt 4118-4196 called late upstream region (LUR), critical for the expression of late genes, has been identified recently. Late genes encode viral capsid proteins that coat viral DNA to form particles and serve as antigen. To elucidate whether there are any sequence variations within LUR of HPV16 and any difference of these sequence variations between cervical invasive squamous cell carcinoma (CIC) and cervical intraepithelial neoplasia (CIN), we sequenced HPV16 LUR from 50 cases of HPV16-positive CIC and CIN. We found that variation frequency in the late upstream region ranged from 0 to 4.2 except for two cases in which variation frequency was as high as 22.8%. Eight of 24 CINs and 17 of 26 CICs contained two or more variations (33% vs. 65%, P < 0.025). The results suggested that the sequence variations occurred more often in LUR of HPV16 than in other regions of HPV16 and the variations in HPV16 LUR might play a role in the process of carcinogenesis of cervical carcinoma.