MYB and leukemia: In vitro experiments with primary cultures from cells of a CMML patient with SETBP1 mutations showed that MYB gene knockdown dramatically inhibited colony-forming capability [74]; indeed, it seems that leukemia cells are more sensitive to a reduction of MYB activity than normal hematopoietic progenitors [117, 118] and that interaction of MYB with P300 is required for MYB-mediated leukemia transformation, but is less critical for normal hematopoiesis [119].