Multidimensional, quantitative assessment of PD-1/PD-L1 expression in patients with Merkel cell carcinoma and association with response to pembrolizumab.
Nicolas A GiraldoPeter NguyenElizabeth L EngleGenevieve J KaunitzTricia R CottrellSneha BerryBenjamin GreenAbha SoniJonathan D CudaJulie E SteinJoel C SunshineFarah SuccariaHaiying XuAleksandra OgurtsovaLudmila DanilovaCandice D ChurchNatalie J MillerSteve FlingLisa LundgrenNirasha RamchurrenJennifer H YearleyEvan J LipsonMac CheeverRobert A AndersPaul T NghiemSuzanne L TopalianJanis M TaubePublished in: Journal for immunotherapy of cancer (2018)
While the binomial presence or absence of PD-L1 expression in the TME was not sufficient to predict response to anti-PD-1 in patients with MCC, we show that quantitative assessments of PD-1+ and PD-L1+ cell densities as well as the geographic interactions between these two cell populations correlate with clinical response. Cell types expressing PD-1 in the TME include CD8+ T-cells, CD4+ T-cells, Tregs, and CD20+ B-cells, supporting the notion that multiple cell types may potentiate tumor regression following PD-1 blockade.