BCL2A1 and acute myeloid leukemia: After a remarkable in vivo clonal expansion of the myeloid progeny derived from a single transduced hematopoietic progenitor with an insertion in the BCL2A1 locus, accompanied by normal blood counts and myeloid differentiation early after transplantation, the animal eventually developed AML derived from the same clone, and died six years post-transplant [1].