PDCD1 and melanoma: However, consistent with previous clinical studies [3, 53, 54] and its highly immunogenic profile, both anti-CTLA-4 and anti-PD-1 antibodies were highly effective in suppressing the growth of the melanoma cell xenografts (Fig. 7b and c), including a significant dose-dependent response with anti-CTLA-4 therapy (Fig. 7b).