MCL1 and acute myeloid leukemia: Moreover, Bcl-xL is more stable than its sister pro-survival proteins BCL-2 and Bcl2 family apoptosis regulator MCL-1.31 In addition, Yagi and colleagues32 determined that expression of dominant-negative Ikaros, found in a subset of acute myeloid leukemia patients, upregulates BCL-XL but not BCL-2.