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The immune checkpoint protein programmed death ligand-1 (PD-L1) is expressed in different types of cancer and is a potential prognostic factor as well as therapeutic target.

This study evaluated PD-L1 expression in the neoplastic progression of vulvar epithelia with respect to the pattern of infiltration in FIGO stages I keratinizing squamous cell carcinomas (SCC). Normal squamous vulvar epithelia (n=20), usual type vulvar intraepithelial neoplasia (uVIN, n=23), differentiated VIN (dVIN, n=21) and FIGO stage I SCC (n=35) were immunostained for PD-L1. In SCC a cohesive growth with well-delineated borders was considered as pushing, dissociative growth in small groups or single cells was defined as diffuse pattern of infiltration. Immunostaining was done with a monoclonal anti PD-L1 antibody (clone SP263, Ventana) and scored to determine up-regulation and overexpression (score 0/1+, 0-5% immunoreactive cells; score 2+, >5 to 50% immunoreactive cells; score 3+, >50% immunoreactive cells). PD-L1 immunoexpression was comparable in normal epithelia and VINs (score 0/1+, n=59; score 2+, n=5, in VINs only; score 3+, n=0), was significantly increased (P<0.0001) in SCC (score 0/1+, n=13; score 2+, n=16; score 3+, n=6), and was related to a diffuse pattern of infiltration (P<0.0001). Staining was accentuated at the invasive margins of SCC frequently. PD-L1 expression is up-regulated in the neoplastic cells of vulvar low stage SCC, related to the development of an invasive phenotype reflecting the initiation of cancer immunoediting, and to an aggressive diffuse type of stromal invasion.


Vulva, Programmed Death Ligand-1, PD-L1, squamous cell carcinoma, pattern of invasion

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Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.