Flourakis et al. (2010) demonstrated that SOCE is the main source of Ca2+ influx that triggers apoptotic cell death in human prostate cancer cells. Orai1 knockdown in cancer cells inhibits SOCE and protects these cells from apoptotic death (Flourakis et al., 2010). Also, the inhibition of STIM1 and Orai1 reduces cell migration and tumor metastasis in breast cancer cells by down-regulating the calcium-dependent focal adhesion pathway (Yang et al., 2009), an effect also seen in cervical cancer (Chen Y. F. et al., 2011, 2013) and hepatocarcinoma cells (Yang et al., 2013). Here, STIM1 is linked to breast cancer.