Specifically, parental and Bcl-xL overexpressing melanoma cells, were implanted in the yolk sack of zebrafish larvae from the transgenic line Tg(mpeg1:mCherry; tnfa:eGFP) 48 h post fertilization (hpf), then macrophage polarization on the tail was analyzed 4 days post injection. This evidence concerns the gene MPEG1 and melanoma.