ABCB1 and acute myeloid leukemia: We then evaluated ORAI1 gene expression in AML#1 and AML#2 primary cells following Ara-C exposure, and we observed, in agreement with the Ara-C effect on SOCE, a significant increase in AML#1 cells with high ABCB1 activity and a significant decrease in AML#2 primary cells (Figure 10).