[Comparison of BCR::ABL (P210) MRNA Levels Detected by DPCR and QPCR Methods in Patients with Chronic Myeloid Leukemia]

To compare digital polymerase chain reaction (dPCR) and real-time quantitative PCR (qPCR) measurements of BCR::ABL (P210) mRNA expression in patients with chronic myeloid leukemia (CML) . In this non-interventional, cross-sectional study, BCR::ABL (P210) mRNA was simultaneously measured by dPCR and qPCR in peripheral blood samples collected from patients with CML who underwent tyrosine kinase inhibitor therapy and who achieved at least a complete cytogenetic response from September 2021 to February 2023 at Peking University People's Hospital. The difference, correlation, and agreement between the two methods were evaluated using the Wilcoxon signed-rank test, Spearman's correlation, and Bland-Altman analysis, respectively. In total, 459 data pairs for BCR::ABL mRNA expression measured by dPCR and qPCR from 356 patients with CML were analyzed. There was a significant difference in BCR::ABL mRNA expression between the two methods (<0.001). When analyzed by the depth of the molecular response (MR), a significant difference only existed for patients with ≥MR4.5 (<0.001). No significant difference was observed for those who did not achieve a major MR (no MMR; =0.922) or for those who achieved a major MR (MMR; =0.723) or MR4 (=0.099). There was a moderate correlation between the BCR::ABL mRNA expression between the two methods (=0.761, <0.001). However, the correlation gradually weakened or disappeared as the depth of the MR increased (no MMR: =0.929, <0.001; MMR: =0.815, <0.001; MR4: =0.408, <0.001; MR4.5: =0.176, =0.176). In addition, the agreement in BCR::ABL mRNA expression between the two methods in those with MR4.5 was weaker than other groups (no MMR: ▉= 0.042, =0.846; MMR:▉=0.054, =0.229; MR4:▉=-0.020, =0.399; MR4.5:▉=-0.219, <0.001) . dPCR is more accurate than qPCR for measuring BCR::ABL (P210) mRNA expression in patients with CML who achieve a stable deep MR.