Occurrence and Expression of Human Papillomavirus Type 16 Genes in Uterine Cervical Carcinomas

The detection of human papillomavirus (HPV) type 16 early genes: E7, E5, and the late gene: L1 was attempted in 42 uterine cervical neoplasia (35 cervical carcinomas and 7 cervical dysplasias) using the polymerase chain reaction (PCR) method. Consequently, E7 gene was detected in 19 (54.3%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, E5 gene was detected in 7 (20.0%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, L1 gene was detected in 18 (51.4%) of 35 carcinomas and in 5 (71.4%) of 7 dysplasias, respectively.　　

In order to elucidate the transcriptional pattern of HPV type 16 in each of the clinical stages, the expression of mRNA for E7, E5 and L1 genes was examined in HPV DNA positive cases using the reverse transcriptase polymerase chain reaction (RT-PCR) method. E7 gene mRNA was detected in 18 (94.7%) of 19 cervical carcinomas, whereas E5 and L1 genes mRNAs were detected in only 4 (57.1 %) of 7 and in one (5.6%) of 18 carcinomas respectively. In cervical dysplasias, E7, E5 and L1 genes mRNA were detected in all cases. E7, E5 and L1 genes were transcriptionally active in all dysplasias, whereas E5 and L1 genes were not always transcriptionally active in carcinomas.　　

These results suggest that the HPV type 16 early gene E7 is present preferentially as integrated form and transcriptionally active in the carcinoma cell, and plays an important role in the development of malignancy. On the other hand, E5 and L1 genes are present and transcribed in the dysplasia cell but their transcriptional activity is less frequent in the carcinoma cell.