A sterile, concentrated (100X) solution intended for use with Medium 254 or Medium 254CF to culture human epidermal melanocytes. Each 5 ml bottle of HMGS contains all of the growth factors, hormones, and tissue extracts necessary for the culture of human epidermal melanocytes and is the correct amount of supplement for a 500 ml bottle of basal Medium 254 or Medium 254CF. When a 500 ml bottle of medium is supplemented with HMGS, the final concentrations of the components in the supplemented medium are: Bovine pituitary extract (BPE) (0.2% v/v) Fetal bovine serum (0.5% v/v) Recombinant human insulin-like growth factor-I (1μg/ml) Bovine transferrin (5μg/ml) Basic fibroblast growth factor (3 ng/ml) Hydrocortisone (0.18μg/ml) Heparin (3μg/ml) Phorbol 12-myristate 13-acetate (PMA) (10 ng/ml)