The dot-blot hybridization of biotin-dUTP-labeled HPV-16 DNA with genomic DNA extracted from biopsies taken from patients with invasive carcinoma and abnormal cytology showed the presence of HPV-DNA in 88% and 80% cases under relaxed conditions and 40% and 20% cases under stringent conditions of hybridization, respectively. Southern blot revealed the HPV-DNA in randomly integrated form in two cases and in episomal form in the other two.