Basal level phosphorylation of GH-regulated intracellular signaling networks like JAK2, STATs 1, 3, 5, ERK1/2, SRC, AKT and mTOR in absence of externally added GH suggested the presence of an autocrine ligand-receptor loop existent and critical in these four melanoma cell lines. The gene discussed is MAPK3; the disease is melanoma.