Clonal Relationship Between Lichen Sclerosus, Differentiated Vulvar Intra-epithelial Neoplasia and Non HPV-related Vulvar Squamous Cell Carcinoma

Differentiated vulvar intraepithelial neoplasia (dVIN) and lichen sclerosus (LS) can give rise to vulvar squamous cell carcinoma (VSCC), but genetic evidence is currently still limited. We aimed to determine genetic abnormalities in VSCC and backtrack these abnormalities in the dVIN and LS lesions. DNA from VSCC and patient-matched dVIN and LS samples of twelve patients was collected. High-resolution genome-wide copy number analysis was performed and subsequently, we sequenced TP53. Copy number alterations were identified in all VSCC samples. One dVIN lesion presented with three copy number alterations that were preserved in the paired VSCC sample. Targeted sequencing of TP53 identified mutations in five VSCCs. All five mutations were traced back in the dVIN (n=5) or the LS (n=1) with frequencies ranging from 3-19%. Our data provide genetic evidence for a clonal relationship between VSCC and dVIN or LS.