PD-L1 receptor expression in vulvar carcinomas is HPV-independent.

PD-L1 (programmed cell death 1 ligand) is expressed on many cancer cells and prevents tumor cell death by blocking T cell activity. PD-L1 overexpression has been reported in squamous cell carcinomas of head and neck and lung cancer. To better understand the role of PD-L1 expression in vulvar cancer, we analyzed PD-L1 expression by immunohistochemistry in 55 well-characterized squamous cell carcinomas of vulva. PD-L1 was found in 72.7% of tumors. 27.3% of vulvar carcinomas showed moderate or strong PD-L1 expression. PD-L1 expression was correlated with low tumor stage (p < 0.05). There was no association to other clinicopathological parameters, HPV status, and overall survival of vulvar carcinoma patients. In conclusion, PD-L1 overexpression is detectable in a substantial proportion of vulvar carcinomas in all stages independent of HPV and may be a suitable therapeutic target in these cancers.