Human Papillomavirus DNA and E6/E7 mRNA Testing as Triage in Liquid-Based Cytology Samples from Primary Screening

Abstract

We estimated the frequency of detection of different human papillomavirus (HPV) types in women with atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous intraepithelial lesion (LSIL) cytology in a population-based primary screening programme. 247 liquid-based cytology (LBC) samples with ASCUS/LSIL results were tested using the LINEAR ARRAY HPV Genotyping Test (LA; Roche Diagnostics), which detects 37 HPV types. 79.4% of samples were positive by LA, and 60.7% were positive for high-risk HPV types (ASCUS: 41.2%; LSIL: 71.0%). 34 of the 37 HPV types included in LA were detected in our samples. HPV16 was detected in 18.6% of samples, and 66.8% of samples contained more than one HPV type, with a maximum of nine types observed in one LSIL sample. A random subset of 47 samples from the 247 samples tested by LA, was also analysed using the AMPLICOR HPV Test (Amplicor, Roche Diagnostics). A separate set of 42 samples, which were positive by LA for the five high-risk HPV types included in the PreTect HPV-Proofer (Proofer, NorChip AS), was also analysed for E6/E7 mRNA expression using Proofer. Concordance between LA and Amplicor was 91.5% (kappa=0.83). One false-negative and three false-positives were recorded for Amplicor, using LA as the "gold standard". Concordance between LA and Proofer was 88.0%; 100% of Proofer samples that were HPV18- positive by LA, and 75.0% of HPV16-positive samples, expressed E6/E7 mRNA. In the present study using LBC samples in a triage situation, where negative predictive value is paramount, LA gave the most reliable results.