Fig. 1

Immunohistochemical expression of Programmed cell death-ligand 1 (PD-L1) (a) high cytoplasmic and membranous PD-L1 expression in DLBCL; stage IV × 400 (b) high cytoplasmic and membranous PD-L1 expression in DLBCL; stage III × 400 (c) low cytoplasmic and membranous PD-L1 expression in DLBCL; stage II × 400 (d) negative cytoplasmic and membranous PD-L1 expression in DLBCL; stage I × 400. (e) Positive cytoplasmic and membranous PD-L1 expression in sections from adenocarcinoma of the colon as appositive control of the marker × 400. (f) Negative control by replacement of the primary anti-PD-L1 antibody by phosphate buffered saline × 400