To confirm the essential changes in the melanocyte, the quantity of melanin production was examined. The melanin content assay showed melanocytes cultured with conditioned medium from SCF-silenced fibroblasts exposed to UVB increased the amount of melanin by about 18%, compared with regular fibroblasts exposed to UVB. This result was consistent with the abovementioned data that melanogenesis-related genes were upregulated. Based on these findings, indeed, SCF silencing caused variations in fibroblasts to paracrine factors, and the variation changed if fibroblasts suffered UVB stimulation. The results from different fibroblasts affected melanocyte activities via melanogenesis-related gene expression. Especially under the condition of fibroblasts with SCF silencing and then exposure to UVB, the melanocytes cultured in fibroblast secretions exhibited increased melanogenesis-related gene levels, and the phenomenon was confirmed by their increased melanin quantities . Analysis of the SCF receptor c-kit mRNA expression level in the fibroblasts showed the c-kit gene level increased under SCF inhibition in fibroblasts and further increased when fibroblasts with SCF inhibition were exposed to UVB. Although c-kit showed increased expression following UVB exposure with or without SCF gene knockdown, the underlying mechanisms need to be confirmed. A probable reason would be that as SCF and c-kit were induced by UVB stimulation and SCF was knocked down, c-kit increased its expression to improve the binding of the ligand to the receptor.