Clinical significance of increased PML-RARa transcripts after induction therapy for acute promyelocytic leukaemia.

Objective: To analyze the clinical and biological significance of the acute promyelocytic leukemia (APL) whose PML-RARa transcripts increased after induction therapy. Methods: We analyzed 9 cases of APL whose PML-RARa transcripts increased after induction treatment and compare them with APL whose PML-RARa transcripts decreased. Results: The only factor affecting increased PML-RARa transcripts was the induction protocol. The cases of increased PML-RARa transcripts received induction treatment mainly based on ATRA and ATO. The evaluation of bone marrow aspirate cytology showed that the cell percentage from myelocyte to segmented neutrophil of the patients with increased PML-RARa transcripts was significantly higher than that of the patients with decreased PML-RARa transcripts. In the follow-up, MRD in 9 cases was consistently negative. Conclusions: Our studies showed the increased PML-RARa transcripts after induction treatment had different clinical significance from the decreased PML-RARa transcripts.