HGF and melanoma: Although the expression of growth factors in melanoma cells was not blocked in this study and endogenous and exogenous level was only measured for HGF, another growth factor considered as important for melanoma [62], it is possible to conclude that endogenous growth factors released by melanoma cells and/or mutation-driven activation of the MAPK-ERK signaling pathway seem to be sufficient to maintain the major functions in a subset of melanoma cell lines.