Molecular monitoring of chronic myeloid leukemia: present and future

Fusion of BCR-ABL1 genes causes chronic myeloid leukemia (CML). As a reliable marker of disease burden, it also serves as the target of tyrosine kinase inhibitors (TKIs). New more sensitive molecular diagnostic tools for BCR-ABL1 can contribute to therapeutic decision-making, especially in considering drug discontinuation for patients enjoying prolonged deep molecular response. Areas covered: Several novel platforms are transforming CML molecular diagnostics to enable faster point-of-care devices, better understanding of clonal diversity and resistance mutations. Here, we review these molecular platforms, knowing implementation in other hematological malignancies will ensue. Expert commentary: Treatment with TKI in CML is the first example of a highly effective targeted therapy. Monitoring of BCR-ABL1 mRNA is standard in assessing disease burden being highly predictive of outcomes recommended by both European LeukemiaNet (ELN) and National Comprehensive Cancer Network (NCCN); however, studies has demonstrated poor adherence to these recommendations. In both clinical practice and assay performance, further optimizing of BCR-ABL1 monitoring can be envisioned including point-of-care methods for increased availability of rapid, standardized testing and increasingly sensitive molecular assays that allow for quantification of MRD and detecting resistance mutations.