OBJECTIVETo understand the predictive value of early monitoring BCR-ABL transcripts in patients with chronic myeloid leukemia (CML) after treatment with tyrosine kinase inhibitor (TKI), and to provides the information for early assessment of prognosis and treatment options.

METHODSBCR-ABL transcripts of 53 CML patients before and after TKI treatment were detected by using real-time quantitative RT-PCR. The relationship between BCR-ABL transcripts level after TKI treatment for 3 months and the later molecular response, progression and mutation was analyzed.

RESULTSThe median values of BCR-ABL transcripts in peripheral blood samples from 30 newly diagnosed patients were 43.99%, which was used as a baseline of BCR-ABL transcripts for molecular response evaluation. Of 53 patients, 31 (58.49%) had a BCR-ABL mRNA ≤ 4.40% (reduced more than 1 log) and 22 (41.51%) greater than 4.40% (reduced to less than 1 log) after 3 months of TKI treatment. The former 31 patients had a significantly higher 18-months cumulative incidence of major molecular response (MMR) (90.32% vs 18.18%, P=0.000) and 3-year cumulative incidence of complete molecular response (CMR) (48.39% vs 0, P=0.000) compared with the latter 22 patients. The lower BCR-ABL level was, the earlier MMR reached. The proportion of patients with a mutation in group of BCR-ABL mRNA>4.40% was significantly higher than that of BCR-ABL mRNA ≤ 4.40% (22.73% vs 0, P=0.021). The incidence of progression increased in group of BCR-ABL mRNA>4.40%, but the difference was not statistically significant (P=0.052).

CONCLUSIONIt is important for the prognosis evaluation of the patients to monitor the level of BCR-ABL transcripts at 3 months after TKI treatment, which might help to early optimization of treatment and to improve curative effect of CML patients.