Identification of HPV genotypes causing cervical precancer using tissue‐based genotyping

Abstract

Identification of high‐risk human papillomavirus genotypes causing cervical precancer is crucial for informing HPV vaccine development and efficacy studies, and for determining which types to include in next‐generation genotyping assays. Co‐occurrence of hrHPV infections is common and complicates carcinogenicity assessment; accurate attribution requires tissue‐based genotyping of precancers. We included all women with cervical intraepithelial neoplasia Grade 2 or worse (CIN2+) from the Biopsy Study, an observational study of 690 women enrolled between 2009 and 2012 at the University of Oklahoma. Tissue‐based genotyping, including whole tissue sections (WTS) and laser‐capture microdissection (LCM), was performed on all precancers with multiple hrHPV infections detected in cytology, totaling over 1,800 HPV genotyping assays. Genotype attribution was compared to hierarchical and proportional hrHPV‐type attribution models. Of 276 women with CIN2+, 122 (44.2%) had multiple hrHPV genotypes in cytology. Of 114 women with genotyping data, 94 had one or more hrHPV detected in tissue. Seventy‐one women (75.5%) had a single causal hrHPV genotype, while 23 women had multiple hrHPV genotypes causing CIN2+. Ten women had multiple causal infections in a single biopsy, contrary to the previous notion that each lesion is caused by a single type only. While HPV16 was the predominant causal hrHPV genotype using all approaches, the hierarchical model overattributed HPV16, whereas other causal hrHPV genotypes, particularly HPV18 and HPV35, were underattributed. Understanding true causal genotypes is important for the evaluation of vaccine efficacy, to estimate the extent of unmasking, and for type‐specific risk assessment in screening and management.

Potential Effects of Human Papillomavirus Type Substitution, Superinfection Exclusion and Latency on the Efficacy of the Current L1 Prophylactic Vaccines

“…Clearly this could provide a rationale for the previously discussed interference between low-risk HPV6/11 and the onset of HPV16-related cervical cancer [39][40][41][42][43]. Furthermore, it has also been reported that individual cells from high-grade CIN3 lesions have only one HPV type present [48] although mixed HPV types have been found in contiguous lesions [49,50]. It is notable that multiple HPV types have been detected in single cells from HPV-positive smear samples, but only in small numbers and when there were no neoplastic changes present [51].…”

“…In this regard, it has been speculated that differences in infectivity between low-risk and high-risk HPV types combined with sexual promiscuity and the use of L1 targeted vaccines, may actually co-operate to drive the evolution of novel high-risk HPV types [55]. As discussed, the evolution of high-grade CIN generally selects for a single HPV type per cell [48][49][50] although there is some limited evidence for intracellular interactions between different HPV types in normal cervical epithelium [51]. If infection with different HPV types does occur in the same cell, this could either activate or suppress the replication of either virus depending on the HPV types present [45].…”

Clinical Significance of the Interaction between Human Papillomavirus (HPV) Type 16 and Other High-Risk Human Papillomaviruses in Women with Cervical Intraepithelial Neoplasia (CIN) and Invasive Cervical Cancer

“…Previous histological microdissection approaches have initially suggested that any individual histological cervical lesion is provoked by a single virus, thus reducing the pathogenetic importance of HR-HPV interactions [ 17 ]. However, recent series suggest that multiple HR-HPVs coexist in about 25% of CIN cases associated with multiple HR-HPVs, underscoring the pathogenetic role of multiple infections [ 18 ]. Pairwise association of HPVs in the literature has been studied mainly on cytologic screening samples obtaining varying results [ 1 , 2 , 4 , 5 ].…”

“…The different methods used, the sociodemographic variability associated with populations studied, the dissimilarity in the prevalence of various HR-HPVs, and the specimens used (cytology vs histology) are some of the possible reasons for the heterogeneity of these results [ 8 ]. The biological mechanisms regulating the dynamics of HPV16 coinfection with other HR-HPV types involve a potential interference in the entry/replication of the viruses, but also in the ability of multiple HR-HPVs to sustain tissue oncogenic transformation in separate lesions or whole tissue sections [ 17 , 18 ]. Studies in vitro suggest that transfection with other HR-HPVs such as HPV18 or HPV45 of cells already infected with HPV16 produces a suppression of the HPV16 genome replication, potentially reducing the infectivity [ 13 ].…”

Multiple human papillomavirus infection and ASCUS-LSIL progression: a review

“…A large number of surveys (1), point out that immunity towards HPV is predominantly type-specific, with limited cross-action. Hence, a better understanding of single-genotype and combined multiple-genotype oncogenic potential has become essential to plan future vaccination schedules and to evaluate the prospective susceptibility to high risk cervical lesions caused by no-targeted high risk (HR)-HPV genotypes in vaccinated cohorts (2). Most of the published population data addressing the role of multiple HR-HPV infections on the severity of cervical dysplasia in women with abnormal cytology consider co-infections as a whole rather than highlighting the interactions of single HPV genotypes.…”