Differences in the integration pattern and episomal forms of human papillomavirus type 16 DNA found within an...

Human papillomavirus (HPV) type 16 DNA was found in three separate neoplastic lesions within a female patient. The physical state of the viral DNA in each lesion was determined by two-dimensional agarose gel electrophoresis. The primary cervical tumor contained large amounts of several distinct episomal forms as well as integrated HPV DNA. Metastatic tumor tissue found in the vagina had greatly reduced levels of episomal DNA and a viral DNA integration pattern that was different from that of the primary tumor. The vulvar carcinoma in situ had what appears to be free and integrated forms of viral DNA. The results show that although metastatic tissue retained HPV DNA, further rearrangements of the integrated viral DNA pattern found in the primary tumor may occur with a dramatic decrease of episomal forms during malignant progression.