Validation of the SPF 10 LiPA Human Papillomavirus Typing Assay Using Formalin-Fixed Paraffin-Embedded Cervical Biopsy Samples

Abstract

Lower levels of performance of human papillomavirus (HPV) typing assays in studies using formalin-fixed paraffin-embedded (FFPE) tissue compared to those using exfoliated cervical cells have been reported. The interpretation of current studies is limited by bias in inclusion criteria, sample matching, and methods of cell collection. We aimed to validate FFPE tissue for typing by the use of the SPF(10) LiPA assay, comparing cervical scrapings to punch and cone biopsy specimens. We examined 165 paired cervical scraping and FFPE punch biopsy samples, and 66 paired FFPE punch and cone biopsy samples. HPV typing was performed using the SPF(10) LiPA assay. Kappa statistics were used to measure interrater agreement. The overall agreement with respect to HPV status was 100%. For 74.5% of subjects (kappa = 0.6147), the same numbers of HPV types were detected in scraping and biopsy specimens. The overall positive typing agreement was 95.4% (range, 93.4 to 97.3) for 441 out of 484 individual HPV type analyses. Agreement was good for HPV-39, -42, -43, and -70 (kappa = 0.6506 to 0.7166), excellent for HPV-6, -16, -18, -31, -33, -35, -40, -51, -52, -56, -58, and -66 (kappa = 0.8499 to 0.9665), and absolute for HPV-11, -44, -45, -53, and -68. In 43.9% of cases (kappa = 0.247), the same numbers of HPV types were found in punch and cone biopsy specimens. Overall positive agreement for typing was 86.8% (range, 82.5 to 91.1) for 204 out of 266 individual HPV type analyses. More infections by HPV-18, -33, -51, and -52 were detected in cone specimens. HPV typing by SPF(10) LiPA performed equally well for cervical scraping specimens and standard pathological material. Some viral types are preferentially detected in cone specimens, likely reflecting better sampling of diseased epithelium and endocervix tissue.