Transcriptional differences of the human papillomavirus type 16 genome between precancerous lesions and invasive carcinomas.

Human papillomavirus type 16 (HPV16) genome DNA and its transcripts in biopsied cervical neoplasias were analyzed by simultaneous extraction of DNA and RNA from one biopsied sample. Southern blot analysis revealed that 5 of 20 cervical intraepithelial neoplasias (CINs) contained HPV16 DNAs existing primarily as episomes and two of seven invasive carcinomas harbored HPV16 genome sequences integrated into the host DNA. Northern (RNA) blot analysis showed that the HPV16 genome sequences were transcriptionally active in the five CINs, as well as in the two invasive carcinomas. The pattern of HPV16-specific transcripts in the CINs was uniform, and the major transcripts were 4.2, 2.2, 1.6, and 1.4 kilobases in size. However, the pattern of HPV16-specific transcripts in the invasive carcinomas was variable and different from that in CINs, suggesting that the alteration of transcriptional pattern might play a key role in the development of malignancy.