Figure 2.

Microscopic features of the tumor: (A) hematoxylin/eosin staining showed heavy lymphocytic infiltration and lymphocytic exocytosis on the neoplastic cells. (B) EBER nuclear reactivity (black-purple) is evident in neoplastic cells. (C) PD-L1 immunohistochemistry shows membranous staining in neoplastic epithelia. (D) PD-1 immunohistochemistry evidences positive staining in infiltrating lymphocytes. EBER = Epstein–Barr encoded small RNA, PD-1 = programmed death 1, PD-L1 = programmed death-ligand 1.