In addition to its repressive effects on IGF-1R and PI3K/AKT/mTOR pathways, inhibition of tumor angiogenesis, aerobic glycolysis, DNA repair, activation of the antitumoral immunity, metformin showed benefic effects on cancer cells by inhibiting mitochondrial complex I and lipid/protein synthesis, regulating glycolysis, glucose level uptake and insulin/insulin-like growth factor signaling availability for tumor cells. The gene discussed is INS; the disease is neoplasm.