FIG. 1.

PCR for the E2 ORF of HPV-16 DNA. Cervical carcinomas positive for HPV-16 DNA were examined for the disruption of the HPV-16 E2 gene by PCR. No amplification of a specific fragment of the E2 gene (1,027 bp) suggested the integration of HPV DNA into the host genome (lanes 1, 4, and 6). When the E2 gene was abundantly amplified, it was postulated that HPV DNA is present in episomal form without any disruption of the E2 gene (lanes 2, 3, 5, and 7).