Emergence of Monosomy 7 in Philadelphia-Negative Cells during MDS Development and not CML Diagnosis Proved by Serial Droplet Digital PCR

ABSTRACT

Emergence of new clonal chromosomal abnormality (CCA) has been reported in Philadelphia-negative cells in patients with chronic myeloid leukemia (CML) undergoing the tyrosine kinase inhibitor (TKI) treatment. However, the time of emergence and clinical significance of CCA remains to be elucidated. In this study, we report a CML patient undergoing TKI treatment who developed myelodysplastic syndrome (MDS) after 206 months since the diagnosis of CML. Results of droplet digital PCR performed with serial bone marrow samples revealed that monosomy 7 in Philadelphia-negative cells appeared at the time of MDS development that did not exist initially at the time of CML diagnosis.