Conversely, no functional role has so far been established for Stim1 and Orai1 paralogues, that is, Stim2 and Orai2, in carcinogenesis, while Orai3 is recruited by Stim1 to activate SOCE and cell proliferation in some oestrogen receptor-negative human breast cancer lines [21]. Here, ORAI1 is linked to breast carcinoma.