STIM1 and neoplasm: Hypoxia and intracellular Ca2+ transients are the basic characteristics of tumors, signaling cascades initiated or regulated by HIF-1 are critical for the process of tumorigenesis (Neumann et al., 2005), and STIM1 mediates SOCE activation and promotes tumor invasion and migration (Van de Vijver et al., 2002; Tsai et al., 2014).