Considering that copper and its chelating agents have been involved in tumor angiogenesis [5], we asked whether copper sulfate (CuSO4) may induce the expression of the pro-angiogenic factor VEGF and its transcriptional regulator HIF-1α in SkBr3 breast cancer cells and HepG2 hepatocellular carcinoma cells. The gene discussed is HIF1A; the disease is breast carcinoma.