This preliminary data suggests that baseline sPD-1 levels could be useful as a prognostic marker to exclude patients with little chance of benefitting from treatment with DCV, and that combining baseline sPD-1 levels with changes in sPD-1 levels after vaccination could be useful as a predictive marker of survival; and, therefore possibly could be a surrogate marker for survival in trials of metastatic melanoma patients treated with DCV. This evidence concerns the gene HOXD13 and metastatic melanoma.