ORAI1 and breast cancer: The information concerning the Orai1 homologs Orai2 and Orai3 is rather scarce but Orai2 has been found to be overexpressed in parathyroid adenoma [15] and acute myeloid leukemia cells [16], while Orai3 is overexpressed in estrogen receptor-expressing (ER+) breast cancer cell lines [17] and in prostate cancer tissue specimens obtained from resection surgeries as compared to noncancerous tissue [18].