Normal human being melanocytes were cultured in basal medium, MCDB153 (Sigma), supplemented with penicillin-streptomycin 50 U/mL (Gibco), Amphoteracin B 0.5 g/mL (Gibco), Alpha-tocopherol 1 g/mL (Sigma), sodium bicarbonate 14.05 mM (Fisher Scientific, Hampton, NH), FBS 4% (HyClone Laboratories, Inc., South Logan, UT), insulin 5 g/mL (Sigma), bFGF 0.6 ng/mL (Sigma), and TPA 80 nM (Sigma)…