Several separate signalling pathways are deregulated in HCC including the Wnt/FZD/β-catenin, PI3K/Akt/mTOR, insulin receptor substrate 1 (IRS1)/ insulin-like growth factor 1 (IGF), and the Ras/Raf/ mitogen-activated protein kinases (MAPK) pathway (Fig. 1). The gene discussed is IRS1; the disease is hepatocellular carcinoma.