Four of six human cervical carcinoma biopsies were shown to contain the DNA of the human papillomavirus type 16 (HPV-16) covalently linked with the tumor cell DNA. HPV-16-specific mRNA species were observed in only one of the four tumors. No such sequences were found in the three other specimens in conditions that permitted the detection of less than one mRNA molecule per cell. It is concluded that maintenance of the malignant nature of these cervical tumors does not depend on the continuous transcriptional activity of

SUMMARYThe DNA of distinct human papillomaviruses (HPVs) is regularly detected in the majority of human cervical carcinomas. In contrast to benign HPV-induced genital lesions, where the viral genomes are exclusively present as episomes, in cervical carcinomas HPV type 16 (HPV16) DNA was found to be integrated into the host DNA. In order to determine the physical state and expression of HPV DNA sequences at different stages of tumour development, we analysed a series of cervical lesions (mild, moderate and severe dysplasia and carcinoma in situ) that are considered precursors of carcinomas of the cervix. In 66.6~ (18 of 27) of the tumours, HPV16 DNA was present. While in mild dysplasias only episomal HPV genomes were found, in all higher grade lesions integration of the viral DNA was detected. There was a close correlation between the episomal state and the expression of the HPV 16 genomes : in 15 cases harbouring episomal HPVI6 DNA (seven of which also contained integrated genomes) viral transcripts were present. We conclude that integration of HPV genomes takes place very early in cervical cancer development. In addition, the episomal state of the viral DNA depends on viral gene expression. The same conclusion, however, is not applicable in those lesions (three severe dysplasias) containing exclusively integrated HPV16 DNA. Thus, HPV16 DNA can persist in an integrated state without recognizable transcriptional activity. These results point to HPVI6 as one potential prerequisite for the first steps in the multistage development of human cervical cancer.

SUMMARYCondylomata acuminata and Buschke-L6wenstein tumours were analysed for the presence of human papillomavirus (HPV) transcripts. HPV DNA and RNA sequences were present in all 13 samples investigated. Ten contained HPV6 and three harboured HPVll. The HPV genomes were found exclusively as extrachromosomal circular molecules. In six biopsy specimens, viral RNA transcripts were not detectable by Northern blot analysis but could be demonstrated in dot blots. From seven HPV6-containing samples it was possible to obtain sufficient amounts of undegraded mRNA. We have found consistently one major species (1.4 kb). Less prominent species of 1.7, 1.85, 2.7 and 3.2 kb, respectively, were also detected. The 3' ends of the HPV6 mRNAs were located between nucleotides 3917 and 4441 in the putative early region and between nucleotides 7232 and 7696 in the putative late region. The arrangement of the 3' termini and the adjacent coding areas within the HPV6 genome show that the RNA species are transcribed from one DNA strand.