One earlier study examined FLT3 mutations in a pediatric APL population; among 29 children, FLT3 mutations were present in 10 (34.5%) of them and were strongly associated with higher leukocyte count.39 The largest study on FLT3 mutations restricted to pediatric patients with APL examined 104 patients aged < 21 years; 81 treated within cooperative group trials CCG-2891 (n=13), CCG-2911 (n=18) and CALGB C9710 (n=50) and 23 treated according to institutional standard therapy.40 This study demonstrated a high prevalence of both FLT3/ITD and FLT3/TKD mutations in childhood APL (40%). The gene discussed is FLT3; the disease is acute promyelocytic leukemia.