Comparison of methods using paraffin-embedded tissues and exfoliated cervical cells to evaluate human papillomavirus genotype attribution

Monitoring the attribution of human papillomavirus (HPV) genotypes to cervical precancerous lesions is essential in assessing the efficacy of HPV vaccines. To resolve the lack of studies comparing the HPV genotyping procedures used to estimate HPV genotype attribution, we undertook a retrospective cross-sectional study to determine the appropriate genotyping procedures for evaluating the potential efficacy of HPV vaccines. Three procedures, including two different genotyping methods, Clinichip HPV test (C-Chip) and modified GP5+/6+ PCR coupled to fluorescent bead sorter detection (MGP), using exfoliated cervical cells (C-Chip and C-MGP, respectively) or formalin-fixed paraffin-embedded tissues (F-MGP), were compared. The overall agreement in detecting high-risk HPV was 88.5–92.1% among the three procedures, and genotype-specific agreement was 83.9–100% for all pairwise comparisons. In cervical intraepithelial neoplasia grade 2/3 specimens, HPV16/18 attribution estimated with the hierarchical attribution method was consistent among the procedures: 52.3% (45/86) for C-Chip, 54.7% (47/86) for C-MGP, and 52.3% (45/86) for F-MGP (P = 0.81). HPV16/18/31/33/45/52/58 hierarchical attribution was 88.4% (76/86) with C-Chip, 86.0% (74/86) with C-MGP, and 83.7% (72/86) with F-MGP (P = 0.49). In cervical intraepithelial neoplasia grade 3 specimens, the corresponding hierarchical attribution was 96.4% (53/55) with C-Chip, 89.1% (49/55) with C-MGP, and 94.5% (52/55) with F-MGP (P = 0.27). Although F-MGP is theoretically a reliable method for determining HPV genotype attribution, it is acceptable to use C-Chip or C-MGP, coupled to the hierarchical attribution formula to correct the bias of multiple infections. These approaches using exfoliated cervical cells are practical for monitoring the efficacy of HPV vaccines.