PD-L1 protein signature in B-cell lymphomas. (A) PD-L1 expression analyzed by RPPA analysis in 10 representative non-GCB DLBCL, 20 representative GCB DLBCL, 10 representative MCL, and 5 representative EBV⁺ B cell lymphoma (BCL) cell lines. Flow cytometry plots show coexpression of PD-L1 and CD20 in 3 representative non-GCB DLBCL cell lines (HBL-1, LP, and WP) and the RC GCB DLBCL cell line, which was used as a negative control for PD-L1 and positive control for CD20 (inset). *EBV⁺ MCL cell line. (B) RPPA heat map showing a cluster based on high PD-L1 expression level on all cell lines analyzed. (C) Proteins within the cluster and their known cellular functions, analyzed by ingenuity pathway analysis.