Detection of HPV in Norwegian cervical biopsy specimens with type-specific PCR and reverse line blot assays

BackgroundAlthough the association of HPV16 and HPV18 DNA with cervical cancers has been well studied, the prevalence of these types in high-grade cervical intraepithelial neoplasias (CIN2/3) may differ from the prevalence found in cervical cancer specimens.ObjectiveTo determine the prevalence of specific HPV types found in high-grade CIN2/3 biopsy samples.Study designOne thousand eight hundred and forty-eight cervical biopsy specimens were obtained from Norwegian women. HPV16 and HPV18 type and gene-specific PCR assays were performed amplifying a portion of the E6, E7 and L1 genes. In addition, the reverse line blot assay was performed on a subset of specimens, in which a portion of L1 was amplified and hybridized to strips coated with complimentary HPV sequences.ResultsThe prevalences of HPV16 and HPV18 in the 1848 biopsy cohort were 32.3% and 6.0%, respectively. HPV16 was detected in 47.5% and HPV18 in 5.9% of diagnosed CIN2/3 specimens. Approximately 12% of the CIN2/3 specimens contained two HPV types and 2.5% contained three HPV types.ConclusionsThe prevalence of HPV16 increases from grades CIN1 to CIN2 to CIN3. The prevalence of HPV18 did not change significantly with increasing CIN grade. The majority of infections diagnosed as CIN2/3 contained a single HPV type. The type-specific PCR assay had increased detection sensitivity over the reverse line blot assay.