Assessment of attribution algorithms for resolving CIN3-related HPV genotype prevalence in mixed-genotype biopsy specimens using laser capture microdissection as the reference standard.

To make accurate determinations regarding potential and actual impact of HPV vaccine programs, precise estimates of genotype-specific contributions to disease are required for pre- and post-vaccine populations. Definitive determination of lesion-specific genotypes, particularly where multiple genotypes are detected in a sample, can be technically demanding and resource intensive; therefore, most prevalence studies use mathematical algorithms to adjust for multiple genotype detections. There are currently several algorithms, which can produce genotype estimates within a wide range of variability. The use of these for cervical cytology samples has recently been assessed for accuracy against a definitive reference standard, but none have yet been assessed for multiple-genotype-containing whole biopsy specimens. Using laser capture microdissection (LCM) on biopsy samples, lesion-specific genotype prevalence data were generated for a cohort of 516 young Australian women (aged 18-32 years) with cervical intraepithelial neoplasia grade 3 or adenocarcinoma in situ. Using whole tissue section genotype data from the same cohort, including 71 (13.7%) with multiple genotypes, lesion-associated genotype prevalence was estimated using four different attribution algorithms. The proportion of lesions attributable to HPV16 and HPV18 by LCM were 58.4% and 5%, respectively; hierarchical, proportional, single type/minimum and any type/maximum attribution estimates were comparable across genotypes. For analyses utilising whole tissue biopsy cervical specimens, attribution estimates are appropriate for estimating the proportional contribution of individual genotypes to lesions in a population.

Follow-up study of HPV58 variants in women with incident HPV58 infection from a Colombian cohort.

Certain variants of human papillomavirus (HPV)type 58 are associated with an increased risk of high grade squamous intraepithelial lesions and cervical cancer. However, little is known about the persistence of HPV58 E6/E7 variants in women with incident HPV58 infections. The aim of the present study was to evaluate the presence and persistence of HPV58 E6/E7 variants in 71 women with incident HPV58 infection throughout their follow-up. These women belonged to a cohort examined in a longitudinal study of 1,610 Colombian women, who were HPV-negative and had normal baseline cytology. E6/E7 DNA regions of HPV58-positive samples were amplified and sequenced using automated direct sequencing. A total of 639 samples were analyzed from the 71 women, and 117 samples (18.3%) were HPV58-positive. HPV58 E6/E7 variants were detected in 85.5% of the samples. The T307/A694/G744/A761 variant was identified in 88% of the samples, the T307/G744 variant was identified in 9% of samples and the T187/T307/A367/G744/G793/T798/A801/T840/C852 was identified in 3% of the samples. Overall, 50% of the HPV58 infections were present after 1 year of follow-up and all infections were cleared after 7 years. Women who had first sexual intercourse at >15 years of age had a lower clearance rate than those who had sexual intercourse for the first time at ≤15 years of age [hazard ratio (HR)=0.29; 95% confidence interval (CI)=0.09-0.92]. Likewise, parous women had a higher clearance rate than nulliparous women (HR=3.43, 95% CI=1.23-9.60). There was no difference in clearance rates between HPV58 E6/E7 variants. In conclusion, HPV58 variants were not associated with persistence of the infection in this group of women.