Identification of E6/E7 Transcription Patterns in HPV 16-Positive Cervical Cancers Using the Reverse Transcription/Polymerase Chain Reaction

Abstract

Studies indicate the presence of four different forms of human papillomavirus (HPV) E6/E7 mRNA resulting from differences in transcription patterns and post-transcriptional nuclear splicing. Through a retrospective analysis of 28 cervical cancer patients, correlations were sought between E6/E7 transcription patterns and histologic type, FIGO stage, and tumor aggression. A combined reverse transcription/polymerase chain reaction was used to study E6/E7 transcription patterns in fresh and/or fixed paraffin-embedded tissues of HPV 16-positive cervical cancers. Random cervical biopsies from nine women with no history of cervical disease were included as controls. Two sets of primers used in the investigations detected the full-length (FL) E6, E6*I, and E6*II mRNAs and the FL E6 and E6*I mRNAs, respectively; eight of the tumors were also analyzed using a third primer combination designed to identify the E6*III mRNA. At least two of the transcripts were detected in all of the tumors, whereas E6/E7 mRNAs were not identified in any of the control cervical biopsies. Overall, the transcription patterns were consistent, but the major E6*I mRNA was not detected in two of the tumors. No relationship was found between the E6/E7 transcription patterns and the histological type and differentiation of the tumors, nor with the FIGO stage and the clinical behavior of the disease. The study confirms that E6/E7 transcription is a constant feature of HPV 16-related carcinoma, but the findings indicate that there may be no clinical advantage in adding E6/E7 mRNA detection to the routine assessment of cervical tumors.