Moreover, by inoculating syngeneic B16-F10 tumors in either bGH mice (high serum GH and IGF1) or GHRKO mice (high serum GH, low serum IGF1), we confirmed that GH directly increases ABCB and ABCG type and IGF1 preferentially increases ABCC type of ABC transporters in melanoma (37). This evidence concerns the gene ABCG2 and melanoma.