Clinical Significance in Detection of Promyelocytic Leukemia-Retinoid Acid Receptor α Fusion Gene in Children

Objective To investigate the clinical significance in the detection of promyelocytic leukemia-retinoid acid receptor α(PML-RARα) fusion gene in children with acute promyelocytic leukemia(APL).Methods RT-PCR was performed to detect PML-RARα fusion gene in 35 children diagnosed as APL according to MIC criteria. The patients were treated with protocol including induction of differentiation with ATRA followed by consolidation therapy with DA, HA or BFM protocol. Results PML-RARα fusion gene was detected in all the 35 children with APL. 3, 21, 6 and 5 patients carried L form, Lform +L form variants, L form variants and S form,respectively. The positive ratios of L form, L form variants and S form were 68.6%, 77.1%, 14.3% respectively. All the 18 patients treated systematically had complete remission(CR) in 14-50 days. In 5 patients who were screened for PML-RARα at this time, 1 patient was negative. The other 4 patients were positive, then they were all negative after the third month after initiation of chemotherapy. 14 patients were followed-up till February 2005. The duration of follow-up was 6 to 36 months in 6 patients, medium duration being 12 months. MRD findings were negative for PML-RARα fusion gene in these 6 patients with consolidation therapy, and they were all in CR.Conclusions Detection of PML-RARα fusion gene using RT-PCR is not only significant for diagnosis, but also helpful for evaluating prognosis and preventing relapse in children with APL.