CTLA4 and cutaneous melanoma: A single-center study of 428 patients with metastatic melanoma (cutaneous in 283, unknown in 55, mucosal in 38, and acral in 22) showed that the median OS of patients with acral melanoma was significantly shorter than that of patients with cutaneous melanoma (17 months vs. 45 months; P = 0.047) after immunotherapy with CTLA-4, PD-1, or PD-L1 inhibitors (84).