In hepatocellular cancer cells, hypoxia also activates an ER Ca2+ sensor, stromal interaction molecule 1 (STIM1), which mediates activation of store-operated Ca2+ entry (SOCE) and leads to upregulation of hypoxia-inducible factor 1 (HIF-1) expression [25, 26]. This evidence concerns the gene STIM1 and hepatocellular carcinoma.