A subset of vulvar carcinomas (VC) are associated with human papillomavirus (HPV
) DNA. This trait can be used to identify tumor markers
for patient's follow-up. A large diversity of HPV
prevalence in VC has been reported, but no data are available concerning the insertional HPV
status in this tumor type. Therefore, we have used an innovative next generation sequencing (NGS)-based CaptHPV method able to provide an extensive characterization of HPV
DNA in tumors.
Material and Methods
Tumor tissue specimens from 55 patients with VC were analyzed using p16 immunohistochemistry, in situ hybridization, polymerase chain reaction, and CaptHPV-NGS assays.
Our analyses showed that 8 (14.5%) of 55 cases were associated with HPV
16 DNA. No other HPV
genotypes were identified. The HPV
genome was in a free episomal state only in one case and both episomal and integrated into the tumor cell genome in 7. There was a single insertion in 5 cases and multiple sites, scattered at different chromosomal loci in two. ISH data suggest that some of these might reflect tumor heterogeneity. Viral integration targeted cellular genes among which were TP63
, and POLA2.
Viral integration at the PKP1
locus was associated with partial gene deletion, and no PKP1 protein was detected in tumor tissue.
Using the NGS-based innovative capture-HPV
approach, we established a cartography of HPV
16 DNA in 8 VC cases and identified novel genes targeted by integration that may be used as specific tumor markers
. In addition, we established a rationale strategy for optimal characterization of HPV
status in VC.