Human papillomavirus in vaginal intraepithelial neoplasia

There are limited data on the prevalence and distribution of human papillomavirus (HPV) genotypes in vaginal intraepithelial neoplasia (VAIN). We sought to clarify this issue in a series of 450 VAIN cases with a confirmed diagnosis between 1990 and 2006. HPV genotyping was performed using paraffin-embedded specimens and polymerase chain reaction (PCR)-based methods. Multiple HPV types were validated by E6 type-specific PCR and direct sequencing. The HPV genotypes of the vaginal and cervical neoplasms were compared for those with incident VAIN and a history of previous/concomitant cervical neoplasms. Ki-67 was performed for supporting diagnosis of VAIN. Of these 450 VAIN cases (median age, 59 years; range, 19-93), two with missing paraffin blocks and 54 with poor DNA quality were excluded. HPV was detected in 273/394 (69.3%) VAIN, and multiple infections were found in 17.9% of HPV-positive samples. The leading types were HPV16 (35.5%), HPV58 (9.9%), HPV52 (9.9%), HPV39 (8.4%), HPV33 (7.3%) and HPV53 (7.0%). Among the 156 cases with a history of previous cervical neoplasia, 29.0% had concordant HPV genotypes, while synchronous VAIN samples (n = 49) were more likely to harbor concordant genotypes (58.7%) with the concomitant cervical neoplasm (p = 0.0003). Whether those HPV types in the incident VAIN lesions had existed in the vaginal epithelium at the time of the previous cervical neoplasia or a new acquisition needs to be clarified in prospective follow-up studies.