Abstract
The prognostic significance of rare BCR-ABL1 transcripts is uncertain in the tyrosine kinase inhibitor (TKI) era. In this retrospective study, 40 (1.7%) patients with rare BCR-ABL1 transcripts were identified from a cohort of 2331 chronic myeloid leukemia (CML) patients; 4 types of rare transcripts were identified, including e1a2 (0.9%), e19a2 (0.4%), e13a3 (0.1%), and e14a3 (0.3%). Compared to patients with the typical transcript, those with the e1a2 transcript had an inferior response to TKIs and a worse outcome. Patients with the e19a2 transcript had a high rate of early optimal response to TKIs, but most of them later lost the complete cytogenetic response (CCyR) due to BCR-ABL1 mutations, resulting in a poor prognosis. Patients with the e13a3/e14a3 transcript responded well to TKIs and had a good outcome. These findings indicate that the type of BCR-ABL1 transcript should be considered when determining the treatment for CML patients in the TKI era.
Potential conflict of interest
Disclosure forms provided by the authors are available with the full text of this article online at https://doi.org/10.1080/10428194.2019.1607329.