KLF1 and acute myeloid leukemia: They showed frequent co-expression of EKLF (24 of 35 GATA1 positives versus 11 of 30 GATA1 negatives, P = 0.010), and median EKLF expression was higher in this subtype than GATA1-negative AML patients (27.4 versus 1.6, P = 0.019) (Table 1).