We proceeded to evaluate the effect of the GH/IGF-1 axis in vivo in mouse syngeneic model for melanoma in C57BL/6J male and female mice transgenic for bovine GH (bGH mice) and in mice insensitive to GH action due to a dysfunctional GHR ‘knock-out’ (GHRKO mice). This evidence concerns the gene IGF1 and melanoma.