Changes in the profiles of the plasma proteins after administration of pembrolizumab. Plasma samples collected before administration of pembrolizumab (screen), on C3D1 or C7D1 were analyzed using an OLINK Immuno-Oncology panel. Normalized protein expression values (NPX) are displayed. (A) Heatmap comparing the normalized expression of 80 proteins (y-axis) in the plasma of patients before and after receiving pembrolizumab (x-axis). Color intensity indicates NPX value. Analytes with a significant increase on C3D1 compared with screening are denoted with asterisks. Plasma protein profiles throughout the treatment were plotted for PD-1 (screen vs C3D1, P < .0001; screen vs C7D1, P = .0076) (B), CXCL9 (screen vs C3D1, P = .0033; screen vs C7D1, P = .0035) (C), and CXCL10 (screen vs C3D1, P = .0978; screen vs C7D1, P = .0427) (D). Statistical significance was evaluated by paired Student t test. P < .05 was considered significant. *P < .05; **P < .01; ****P < .0001. Ns, not significant; Ref, healthy donor control reference.