Relationship between E6-E7 lineage sequences, viral loads, and integration of HPV16 in women with atypical squamous cells of undetermined significance (ASCUS) pap smears

Abstract

HPV16 DNA associated with histologic high-grade precancer lesions (cervical intraepithelial neoplasia grade 2 or 3 [CIN2 or CIN3]) is sometimes found in women with atypical squamous cells of undetermined significance (ASCUS) Pap smears, the mildest form of cellular abnormality in a cervical smear. This study evaluated, in a population of patients with ASCUS Pap smears, the prevalence of different HPV16 lineages (or isolates) and the physical status, total viral load, and integrated viral load of HPV16 DNA in a population, stratified by HPV16 isolates (primarily either EUR-350T or EUR-350G) that was found. We demonstrated, in smears of women diagnosed with ASCUS and infected with EUR-350G HPV16 isolates (sublineage A1) that both the physical status of HPV16 and the distribution of integrated HPV16 DNA viral loads were different when compared to a population infected with EUR-350T HPV16 isolates. We showed that the mean and median percentages of HPV16 DNA were higher, and a distribution of log 10 integrated HPV16 viral load was more homogeneous in a population infected with EUR-350G HPV16 isolates than in a population infected with EUR-350T HPV16 isolates. No difference was found in terms of total HPV16 viral load between these two isolates. Here, we investigate E6-E7 sequencing as an easy technique to detect women with a greater proportion of integrated HPV genome, and we suggest an adaptation of the current protocol for monitoring women with ASCUS Pap smears.