Acute promyelocytic leukemia with STAT5b-RARα fusion gene positive: report of one case and review of literature

Objective To investigate the diagnosis, treatment and prognosis of acute promyelocytic leukemia (APL) with NPM-RARα fusion gene positive. Methods One APL patient with NPM-RARα fusion gene positive who was diagnosed by using morphology, immunology, cytogenetics, molecular biology and multiplex fluorescence in situ hybridization in Changhai Hospital in November 2014 was retrospectively analyzed, and the patient was induced with retinoic acid and treated with DA(daunorubicin + cytarabine) regimen, followed by 4 courses of cytarabine consolidation therapy. Results Abnormal promyelocyte accounted for 0.64 by morphology. And the group of cells expressed myeloperoxidase (MPO), CD13, CD15, CD117, and CD7, CD11c, CD79a, CD123 weakly expressed or not by immunophenotype analysis; karyotype analysis showed 45, XY, t(5;17), 7p-, -16[8]/46, idem, +20[5]/45, idem, -8, +20[2]/46, XY[5]; the fusion gene screening showed that the expression level of NPM-RARα was 416.98% compared with that of APL; molecular complete remission was obtained after the consolidation therapy, but the patient relapsed after 34 months. Finally, the patient died of abnormal coagulation and respiratory failure, with overall survival of 35 months. Conclusion APL with NPM-RARα fusion gene positive is a rare type of acute leukemia, and the main treatment method is retinoic acid combined with myeloid chemotherapy regimen, which has a favorable efficacy but a poor prognosis. Key words: Leukemia, promyelocytic, acute; NPM-RARα; Diagnosis; Prognosis