NPM1 and myelodysplastic syndrome: In a phase 1 study, Selinexor, a selective inhibitor of nuclear export compound (SINE) that functions to block XPO1, was studied in a dose escalation trial in patients with relapsed or refractory AML, adults > 60 years old with MDS or unfavorable cytogenetics, and patients > 70 years old who were not chemotherapy candidates; 17% of the patients enrolled had NPM1 mutations [56].