Human papillomavirus (HPV) study of 2916 cytological samples by PCR and DNA sequencing: genotype spectrum of patients from the west German area.

Human papillomaviruses (HPVs) are aetiological agents for cervical cancer. More than 70 different HPV types that infect genital mucosa have been found. In order to develop a sensitive and specific detection and typing assay, a PCR/direct sequencing approach was used. Two pairs of consensus primers were used for amplification of HPV DNA and the PCR products obtained were analysed by automated sequencing. Sequences were compared with those in GenBank by using the BLAST program. In this study, 2916 cytological samples were screened for HPV, as well as for triage. Nine hundred and forty-eight (32.5%) samples were positive for HPV, of which 134 harboured more than one HPV type. Of the 948 PCR-positive samples, 648 were typed. Thirty-nine different HPV types were identified by sequencing. The two most frequently found HPV types, 16 and 31, together accounted for 36.3% of the sequences (26.2 and 10.1%, respectively). This group was followed by HPV types 6 (5.7%), 18 (5.3%), 58 (4.5%), 61 (4.5%), 53 (4.4%), 42 (4.3%) and 51 (4.0%). All other types were detected at frequencies <4% and eight types were detected only once. PCR/direct sequencing is a reliable method for routine detection of HPV in cytological samples. The data presented here suggest a complex distribution of HPV types in the population tested. The results accentuate the importance of PCR-based techniques in HPV diagnosis, as hybridization-based methods can only detect a limited number of infections. This method can also be applied easily to the analysis of tissue samples and it therefore also allows type-specific follow-up of women who have been treated for cervical intraepithelial neoplasia.