Figure 4. PD-1, but not its ligands, is frequently expressed in tumor biopsies.

(A) PD-1 expression on PBT, melanoma, Lung specimens (control or tumoral) and RCC (benign and tumoral). PD-1 level is expressed as a ratio relative to the MFI of the control isotype. Bars correspond to the Median; * p<0.05, ** p<0.01, *** p<0.001 (Mann Whitney). (B) Percentage of tumor biopsies showing positivity for PD-L1 or PD-L2 staining (Melanoma n = 15; NSCLC n = 15; RCC n = 12).