BCL-XL inhibits apoptosis, while BCL-XS promotes apoptosis; BCL-XL is highly expressed in myeloid leukemia and indicates a poor prognosis, while BCL-XS is expressed at low levels in renal cancer, liver cancer, breast cancer, prostate cancer, and other tumor cell lines (5, 6). Here, BCL2L1 is linked to myeloid leukemia.