Anti-CD57 marks a subset of lymphocytes known as natural killer (NK) cells. Follicular center cell lymphomas often contain many NK cells within the neoplastic follicles. Anti-CD57 also stains neuroendocrine cells and their derived tumors, including carcinoid tumor and medulloblastoma. Anti-CD57 can also be useful in separating type B3 thymoma from thymic carcinoma when combined with a panel that includes antibodies against GLUT1, CD5, and CEA. This antibody is available purified with BSA/azide at 200 ug/mL, or BSA/azide-free at 1 mg/mL.