HPV 16 Variants in Invasive Cancers in the US Prior to HPV Vaccine Implementation

Abstract

BackgroundFew studies have examined genetic variants of HPV 16 in cancers other than cervical.
 
MethodsResidual DNA extracts from samples collected from seven cancer registries as part of a pilot study to determine type‐specific HPV prevalence in US cancers prior to vaccine introduction were used. Of the 1395 histologically confirmed tumors with HPV PCR results, 1045 (74.9%) were HPV 16 positive. Valid E6 pyrosequencing allowed variant determination in 836 (80%) of the HPV 16 tumors (107 anal, 337 cervical, 30 penile, 25 vaginal, 69 vulvar and 268 oropharyngeal). Variants were designated using both geographic and group terminology for lineages. Age, sex and race/ethnicity were obtained from the registry data.
ResultsEuropean (A) lineages were the most prevalent in all cancer sites, ranging from 77.5% for penile to 95.7% for anal cancers. Within the A lineage, the E‐p and E‐T350G variants were the most common, ranging from 28‐41% and 20.5 – 33% respectively. Other non‐European variants (lineage B, C, D) were distributed in similar levels among the different cancers, with prevalence rates of less than 10% (except for AA/NA‐1 (D) lineage variants in cervical cancers‐ 12.2%). The odds ratio of European to non‐European variants was 2.8 in anal compared to cervical cancer [95% Confidence Interval 1.40 – 5.86]. Variant association with race ethnicity was: European (A) with white non‐Hispanic (NH); Eur‐AS with Asian, Pacific Islander, Af1 (B) with black NH, and AA/NA‐1 (D) with Hispanic.
ConclusionsRace/ethnicity is associated with HPV 16 variants. HPV 16 European (A) variants were predominant in cancers from all primary sites.