Objective: To establish and evaluate a real time quantitative PCR (RQ-PCR) method for detection and quantification the PML/RAR alpha 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/RAR alpha 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/RAR alpha 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/microL were obtained, while reproducible maximal sensitivity achieved 100 copies/microL. In 10 normal controls, no amplified fluorescent signals were detected. The median absolute and normalized amount of PML/RAR alpha fusion gene transcripts were 4.27 x 10(3)-3.36 x 10(5) copies/50 ng (median 4.33 x 10(4)copies/50 ng) and 29.38%-600.53% (median 48.12%) respectively. One case showed significant decrease of PML/RAR alpha fusion gene transcripts after induction therapy compared to that at the time of diagnosis, while the fusion transcripts significantly 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.