In particular, it has been reported in a pilot study that high pre-treatment serum VEGF levels in patients with advanced melanoma may predict poor responses to ipilimumab (anti-cytotoxic T-lymphocyte associated protein 4 antibody), while it was not identified as a predictor of poor responses in patients treated with pembrolizumab (anti-PD-1 antibody) alone or ipilimumab plus nivolumab (anti-PD-1 antibody) (33). This evidence concerns the gene PDCD1 and melanoma.