Growing body of evidence indicates that SOCE in cancer cells is mediated by Stim1, which relays the information relative to the drop in ER Ca2+ levels to cell periphery, where it binds to and activates Orai1, a highly Ca2+-selective pore-forming unit [10, 13, 14, 17, 20, 21, 42, 44]. This evidence concerns the gene STIM1 and cancer.