Collectively, our data suggest that dexamethasone-resistant RS4;11 cells are a subpopulation of B-ALL cells that carry FLT3-ITD or R845G mutations, and therefore it could prove useful to screen B-ALL patients who are resistant to dexamethasone for mutations in FLT3, which then could be targeted with FLT3 inhibitors that are already available on the market. The gene discussed is FLT3; the disease is acute lymphoblastic leukemia.