To identify unknown immune evasion mechanisms allowing melanoma cells to circumvent recognition by specific CTL, the human HLA-A*0201-positive melanoma cell line UKRV-Mel-15a expressing the transmembrane tumor antigen Melan-A/MART-120, 24, 25 was co-incubated with an HLA-A*0201-restricted Melan-A/MART-126-35-specific CTL clone. The gene discussed is MLANA; the disease is melanoma.