Chemoresistance pathways involving Orai calcium channels. Orai calcium channels are able to modulate sensitivity to chemotherapy. Processes known to alter chemoresistance are highlighted in bold. These include calcium overload, MultiDrug Resistance (MDR), autophagy, modulation of signalling pathways (MAPK and PI3K-Akt/Sgk), transcription factors (NF-κB, c-myc, p53), and EMT (Epithelial to Mesenchymal Transition). Processes initiated by Orai1 and Orai3 are summarized by purple and blue arrows, respectively. The dashed arrows are not different from plain arrows, except that they cross other arrows.