Continued expression of the oncogenes E6 and E7 of human papilloma virus "high risk" type 16 (HPV16) initiates neoplastic transformation and maintenance of the malignant phenotype in cervical carcinoma cells. The transcriptional activity of the HPV16 E6/E7 oncogenes was investigated in HPV16-containing cervical cell lines, cervical carcinomas, and cervical intraepithelial neoplasia grade III lesions using the techniques of reverse transcription-polymerase chain reaction (RT-PCR), Southern blotting, and in situ hybridization. To facilitate detection of the full-length HPV16 E6/E7 oncogene transcript and its characteristic splice products E6*I and E6*II in cervical tissues, a nested RT-PCR (nRT-PCR) assay was designed. Specific detection of HPV E6/E7 oncogene transcripts in clinical specimens was found to be improved by nRT-PCR, being as sensitive as the combination of conventional RT-PCR and subsequent Southern blot hybridization. Regarding the progression of premalignant lesions to cervical cancer, detection of the HPV transcriptional activity by nRT-PCR may provide additional information for risk evaluations. Moreover, improvements in the amplification of HPV oncogene transcripts may also be advantageous for monitoring the activity of HPV before and after transcript-targeted gene therapy of cervical cancer.