RESUMO
<p><b>OBJECTIVE</b>To screen the potential protein biomarkers in minimal residual disease (MRD) of the acute promyelocytic leukemia (APL) by comparison of differentially expressed serum protein between APL patients at diagnosis and after complete remission (CR) and healthy controls, and to establish and verify a diagnostic model.</p><p><b>METHODS</b>Serum proteins from 36 cases of primary APL, 29 cases of APL during complete remission and 32 healthy controls were purified by magnetic beads and then analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The spectra were analyzed statistically using FlexAnalysis(TM) and ClinProt(TM) software.</p><p><b>RESULTS</b>Two prediction model of primary APL/healthy control, primary APL/APL CR were developed. Thirty four statistically significant peptide peaks were obtained with the m/z value ranging from 1000 to 10 000 (P < 0.001) in primary APL/healthy control model. Seven statistically significant peptide peaks were obtained in primary APL/APL CR model (P < 0.001). Comparison of the protein profiles between the two models, three peptides with m/z 4642, 7764 and 9289 were considered as the protein biomarker of APL MRD. A diagnostic pattern for APL CR using m/z 4642 and 9289 was established. Blind validation yielded correct classification of 6 out of 8 cases.</p><p><b>CONCLUSIONS</b>The MALDI-TOF MS analysis of APL patients serum protein can be used as a promising dynamic method for MRD detection and the two peptides with m/z 4642 and 9289 may be better biomarkers.</p>