HO-1 is known to promote cell proliferation in melanoma through the B-Raf-ERK signaling pathway [20], thus suggesting that the CoPP-induced HO-1 could have also promoted ARPE-19 cell proliferation through the activation of the same signaling pathway, which led to the overexpression of Ki-67 and TGFβ1. This evidence concerns the gene TGFB1 and melanoma.