NFATC1 and acute lymphoblastic leukemia: ICN1; RCT2; Nfat1-/-; Nfat2fl/del; Nfat4fl/fl T-ALL cells were co-cultivated in vitro with MS5 cells as MS5 stromal cells are required for survival and proliferation of ICN1 T-ALL cells ex vivo [8] and treated either with 4-hydroxytamoxifen (4OHT) to induce deletion of Nfat2 and Nfat4 or with the carrier solvent (Et), as control [6, 8].