Inhibition of calmodulin (CGS9343B) and ROCK-RhoA (HA1100), which have been shown to regulate NHE1 activity in cardiac myocytes [24] and fibroblast cells [25], had no effect on cell growth or pHi in AML cell lines (Supplementary Fig. S3E, F). This evidence concerns the gene RHOA and acute myeloid leukemia.