[Comparisons of conventional and normalized calculation of quantitative real-time RT-PCR detecting PML-RAR alpha fusion gene in patients with acute promyelocytic leukemia].
OBJECTIVE
To optimize the calculation of quantitative real time RT-PCR (Q-RT-PCR) of PML-RARalpha in patients with acute promyelocytic leukemia (APL) for molecular monitoring of minimal residual disease (MRD).


METHODS
By using both regular reverse transcription polymerase chain reaction (RT-PCR) and Q-RT-PCR, the expression levels of PML-RARalpha transcripts were measured before and after treatment. The conventional Q-RT-PCR calculation was directly compared the post-treatment transcript level with the respective pre-treatment one (DoseN) in the individual patient while the standardized calculation was based on the calculation of standardized pre-treatment DoseN of all patients.


RESULTS
In 181 samples from 31 patients, the results of log-reduction of PML-RARa after induction, at the end of consolidation and during maintenance by conventional method were (1.9 +/- 1.9), (4.8 +/- 1.3) and (5.7 +/- 0.4), respectively, while by standardized method were (2.0 +/- 1.9), (4.9 +/- 1.4) and (5.7 +/- 0.1), respectively. Of notice, the result was with significant less variation of the latter methods during maintenance therapy. Moreover, with defined criteria of molecular response (3.0-4.9 log-reduction as minor and > or = 5.0 log-reduction as major molecular response), the standardized method was validated in clinical settings.


CONCLUSIONS
The standardized method is superior to the conventional method for calculation of Q-RT-PCR results. The new method can reduce the individual variation in monitoring the MRD and is feasible even for patients with unavailable pre-treatment samples.
Department of Hematology, RuiJin Hospital, Shanghai Institute of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
Jiong
J
Hu
Xiao-Dong
XD
Gao
Yuan-Fang
YF
Liu
Yong-Mei
YM
Zhu
Jun-Min
JM
Li
Zhi-Xiang
ZX
Shen
D005500:Follow-Up Studies; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*
D015514:Oncogene Proteins, Fusion; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein