Clinical significance of programmed death 1/programmed death ligand 1 pathway in gastric neuroendocrine carcinomas

Figure 1 Immunohistochemical staining for programmed death ligand 1 in human gastric neuroendocrine carcinomas. A: Representative case of negative programmed death ligand 1 (PD-L1) expression; B: Tumor-stromal interface enhanced expression of PD-L1; C: Membrane expression of PD-L1; D: Weak staining; E: Moderate staining; F: Strong staining. PD-L1: Programmed death ligand 1.

Figure 2 Immunohistochemical staining for programmed death 1, CD8, and FOXP3 in human gastric neuroendocrine carcinomas. A: The programmed death 1 positive infiltrating lymphocytes; B: CD8 positive lymphocytes; C: FOXP3 positive Treg cells.

Figure 3 Kaplan–Meier survival analysis of the gastric neuroendocrine carcinomas patients. A: Patients with high infiltration of CD8⁺ lymphocytes tended to have a relative longer survival, but the difference was not statistically significant; B: Kaplan-Meier overall survival curves in patients with high and low expression of programmed death ligand 1 (PD-L1) in the whole population; C: Low PD-1⁺ cell infiltration group; D: High PD-1⁺ cell infiltration group. PD-L1: Programmed death ligand 1.

Figure 4 Programmed death ligand 1 copy number is associated with programmed death ligand 1 expression in gastric neuroendocrine carcinomas. A: Programmed death ligand 1 (PD-L1) copy number status varied in 19 gastric neuroendocrine carcinoma samples. The cases with copy number gain are shown in black; B: Cases with copy number gain showed significantly higher PD-L1 expression than those without. PD-L1: Programmed death ligand 1.