Development of acute myeloid leukemia associated with Ph-negative clone with inv(3)(q21q26) during imatinib therapy for chronic myeloid leukemia

Occurrence of chromosomal abnormalities in Philadelphia chromosome-negative metaphases in patients with chronic-phase chronic myeloid leukemia undergoing TKI treatments

Forty-three chromosomal abnormalities in Philadelphia-negative metaphases (Ph-CAs) appeared in 35 of 432 patients in chronic phase chronic myeloid leukemia (CP-CML) undergoing tyrosine kinase inhibitor (TKI) treatments. These CAs were mostly common in trisomy-8 (16 cases), trisomy-Y (five cases), and monosomy-7 (five cases). Furthermore, Ph- CAs were significantly associated with higher platelet count (494 × 10⁹/L vs. 326 × 10⁹/L, p = .006), and higher incidence of true clonal evolution in Ph-positive metaphase (22.9% vs. 9.1%, p = .017). Additionally, patients with Ph- CAs had worse rates of complete cytogenetic remission (76% vs. 86%, p = .0091), major molecular remission (55% vs. 76%, p = .001), progression-free survival (47% vs. 86%, p < .001), but a similar overall survival rates compared to those in patients without Ph- CAs. In conclusion, Ph- CAs may predict worse response to TKI therapies and survival in patients with CP-CML, thus requiring close cytogenetic monitoring.

Philadelphia chromosome-negative acute myeloid leukemia with 11q23/MLL translocation in a patient with chronic myelogenous leukemia

Although defined by the presence of t(9;22), chronic myelogenous leukemia (CML) can have other concurrent additional cytogenetic changes, especially during disease progression. Additional chromosomal changes (ACAs) in CML often occur in Philadelphia chromosome (Ph)-positive cells and are associated with disease acceleration and treatment resistance. Occasionally chromosomal changes occur in Ph-negative cells and this phenomenon is often transient and does not correlate with disease progression. Very rarely myelodysplastic syndrome or acute leukemia can develop in Ph-negative cells. In this study, we report an unusual case of acute myeloid leukemia (AML) with 11q23/MLL translocation emerging from Ph-negative cells in a patient with CML.