Quantification of PML/RARα fusion gene transcripts in patients with acute promyelocytic leukemia by using realtime quantitative PCR

Objective To establish and evaluate a real time quantitative PCR （RQ-PCR） method for detection and quantification the PML/RARα fusion gene transcripts in patients with acute promyelocytic leukemia （APL）. Methods Three pairs of primers and TaqMan probe were designed for detecting the most frequent PML/RARα transcripts （L- form, S-form and V-form） and normal ABL was used as an internal control. A real time PCR condition was established to detect PML/RARα and ABL positive templates with a series of dilutions. To evaluate this assay, bone marrow samples from 6 APL patients were detected. Results In repeated tests, maximal sensitivities of 10 copies/μL were obtained, while reproducible maximal sensitivity achieved 100 copies/μL. In 10 normal controls, no amplified fluorescent signals were detected. 3he median absolute and normalized amount of PML/RAα fusion gene transcripts were 4.27 × 10^3-3.36 × 10^5 copies/50 ng （median 4.33×10^4 copies/50ng） and 29.38%-600.53% （median 48.12%） respectively. One case showed significant decrease of PML/RARα fusion gene transcripts after induction therapy compared to that at the time of diagnosis, while the fusion transcripts significandy increased after relapsed. Conclusion RQ-PCR is a sensitive, reliable quantitative assay and can be used in the diagnosis of APL and measurement of MRD. Key words: real-time quantitative PCR;  acute promyelocytic leukemia;  fusion gene