Blockade of proliferative pathways by inhibiting MEK is growth inhibitory or pro-apoptotic in some acute myeloblastic leukemia (AML) cell lines and some AML patients (Berra et al., 1998; Jarvis et al., 1998; Milella et al., 2001; Morgan et al., 2001; Baines et al., 2002). Here, MAP2K7 is linked to acute myeloid leukemia.