ORAI1 and in situ carcinoma: The increase in the extracellular Ca2+ concentration to 2 mM led to much higher spontaneous Ca2+ influx in cells transfected with Orai1 plus STIM1-N-CIS-DelIH than in cells transfected with Orai1, Orai1 plus STIM1-N-CIS or Orai1 plus STIM1-FL.