Prognostic Role of Tumoral PDL1 Expression and Peritumoral FoxP3+ Lymphocytes in Vulvar Melanomas

Publication date: Available online 4 January 2018
Source:Human Pathology
Author(s): Agata Chłopik, M. Angelica Selim, Yan Peng, Cheng-Lin Wu, Gemma Tell-Marti, Kristen M. Paral, Sara C. Shalin, Stefan Kraft, Chao-Kai Hsu, Christopher R. Shea, Susana Puig, Maria-Teresa Fernandez-Figueras, Wojciech Biernat, Janusz Ryś, Andrzej Marszalek, Mai P. Hoang
Prognostic role of PDL1 expression, CD8+ and FoxP3+ lymphocytes in vulvar melanomas has not been studied. We correlated PDL1 expression, and CD8+ and FoxP3+ immune infiltrates with clinicopathologic variables and patient outcomes in a series of 75 vulvar melanomas. Tumoral PDL1 expression (>5%) was seen in 23% of cases. By Fisher's Exact test, PDL1 expression and peritumoral FoxP3+ lymphocytes significantly correlated with less disease-specific death. By linear regression analysis, correlations between tumoral PDL1 expression with the density of tumoral CD8+ and peritumoral CD8+ lymphocytes; tumoral FoxP3+ with tumoral CD8+ lymphocytes; and peritumoral FoxP3+ with peritumoral CD8+ lymphocytes were observed. By univariate analyses, tumor thickness > 4mm predicted poorer progression-free survival, melanoma-specific survival and overall survival. PDL1 expression > 5%, peritumoral CD8+, peritumoral FoxP3+ and tumoral FoxP3+ lymphocytes correlated with better overall survival. By multivariate analyses, high peritumoral FoxP3+ lymphocytes independently predicted better melanoma-specific survival (p=0.023); and tumor thickness independently predicted poorer progression-free survival (p = 0.05) and overall survival (p = 0.039). In conclusion, our study shows that independent from tumor thickness an increased density of peritumoral FoxP3+ lymphocytes may positively impact survival in a subset of vulvar melanomas. Tumoral PDL1 expression correlated with tumoral as well as peritumoral CD8+ and FoxP3+ lymphocytes, supportive of an adaptive immune response. Although the frequency of PDL1 expression is low in vulvar melanoma, its expression may identify a subset of vulvar melanoma that might respond to immunotherapy.



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