IL2 and metastatic melanoma: Melanoma is considered an immunogenic cancer, based on several observations including: 1) the frequency of spontaneous regressions of metastatic melanoma (often accompanied by vitiligo); 2) the prognostic significance of the density of tumour-infiltrating-lymphocytes in the primary lesions; and 3) the efficacy of non-specific immune stimulation with interleukin-2 (IL-2) for advanced disease.