Furthermore, there are studies that illustrate treatment approaches in the case of a melanoma of unknown primary [57], describing cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4, ipilimumab) and programmed death protein-1 (PD-1) antibodies (PD-1, nivolumab), with a poor prognosis (4-months’ survival). The gene discussed is CTLA4; the disease is melanoma.