Clinical significance of FLT3 internal tandem duplication in patients with acute promyelocytic leukemia

Abstract

Objective To evaluate the mutation of FLT3 internal tandem duplication(FLT3-ITD)in acute promyelocytic leukemia(APL)and its clinical significance. Methods Polymerase chain reaction(PCR)was used to detect FLT3-ITD mutations from 30 newly diagnosed APL patients. Clinical features and therapeutic efficacy were compared between ITD positive and wild-type patients. Results Among the 30 APL patients, 8(26.7 %)patients were FLT3-ITD positive. Patients with FLT3-ITD mutation presented significantly higher peripheral white blood cell count(WBC)[WBC: 20.48 × 109/L(0.74-74.3)× 109/L vs 1.75 × 109/L(0.78-35.3)× 109/L, P= 0.024]and higher lactic dehydrogenase(LDH)level [LDH: 447.5 U/L(191-1 533)U/L vs 205.0 U/L(118-743)U/L, P= 0.016], and significantly lower platelet count(Plt)[Plt: 14 × 109/L(6-59)× 109/L vs 30 × 109/L(9-124)× 109/L, P= 0.021]as compared with wild-type FLT3 patients(P 0.05). And there were also no significant differences between the two groups in complete remission(CR)rate, the time of getting CR, the occurrence of retinoic acid syndrome(RAS), disseminated intravascular coagulation(DIC)as well as overall survival rate(after a median follow-up of 17 months)(P > 0.05). Conclusions FLT3-ITD is frequently identified in patients with newly diagnosed APL. FLT3-ITD mutation is associated with higher initial WBC and LDH, and lower Plt. No significant influence on treatment outcome is observed with a short-term follow-up. Key words: Leukemia, promyelocytic; Gene, FLT3; Mutation