PDCD1LG2 and melanoma: The cell surface protein expression patterns of these markers in our melanoma panel did not precisely reflect their transcript expression patterns in the human SKCM dataset of TCGA (n = 472; Figure 1D), although both protein and transcript expression of PD-L2 (PDCD1LG2) and HLA-DR (HLA-DRA) were correlated (Figures 1E,F).