Ca2+ signalling is dysregulated in many cancer cells, often through over- or under-expression of calcium channels (e.g., stromal interaction molecule 1, STIM1; Calcium release-activated calcium channel protein 1; Transient receptor potential channels; IP3 (inositol 1,4,5-trisphosphate) receptor; and L-type voltage-gated calcium channels, Cav1) [99]. The gene discussed is STIM1; the disease is cancer.