ERG and acute myeloid leukemia: Immunohistochemistry further showed high expression of ERG and CD56 (markers associated with C/G AML; refs. 11, 13, 20) in the mouse bone marrow, characteristic of this type of leukemia, and similar to the high CD56 expression in leukemia aggregates present in a bone marrow biopsy from a C/G patient (Figure 1E).