%0 Journal Article %T Clinical Features of Clonal Cytogenetic Abnormalities in Philadelphia-negative Cells Developed During Tyrosine Kinase Inhibitor Treatment. %A Oiwa K %A Lee S %A Fujita K %A Ueda T %A Yamauchi T %J Intern Med %V 63 %N 5 %D 2024 Mar 1 %M 37468240 %F 1.282 %R 10.2169/internalmedicine.2182-23 %X Most clonal cytogenetic abnormalities of Philadelphia-negative cells (CCA/Ph-) occurring during tyrosine kinase inhibitor (TKI) treatment are transient, and the development of secondary myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) is rare, but the frequency and clinical significance in Japanese patients are still unknown. We herein report four patients who developed CCA/Ph- during TKI therapy and were diagnosed with secondary MDS/AML. The duration from TKI therapy initiation to MDS/AML onset ranged from 3 to 48 months, and the survival ranged from 5 to 84 months. The occurrence of CCA/Ph- with MDS/AML may be associated with a poor prognosis, and careful follow-up is recommended for patients who receive TKI therapy.