Genomic studies have revealed significant branching heterogeneity in cancer. Studies of resistance to tyrosine kinase inhibitor therapy have not fully reflected this heterogeneity because resistance in individual patients has been ascribed to largely mutually exclusive on-target or off-target mechanisms in which tumors either retain dependency on the target oncogene or subvert it through a parallel pathway. Using targeted sequencing from single cells and colonies from patient samples, we demonstrate tremendous clonal diversity in the majority of acute myeloid leukemia (AML) patients with activating internal tandem duplication mutations at the time of acquired resistance to the FLT3 inhibitor quizartinib. These findings establish that clinical resistance to quizartinib is highly complex and reflects the underlying clonal heterogeneity of AML.
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http://dx.doi.org/10.1182/blood-2016-04-711820 | DOI Listing |
Eur J Haematol
January 2025
Hematology Unit, Azienda Ospedaliera Annunziata, Cosenza, Italy.
FLT3 mutations are among the most common genetic alterations in acute myeloid leukemia (AML) and are associated with poor prognosis. Significant advancements have been made in developing FLT3 inhibitors (FLT3Is), such as quizartinib, which have improved treatment outcomes in both newly diagnosed and relapsed/refractory AML. Resistance to FLT3Is remains a major clinical challenge, driven by diverse mechanisms including FLT3 point mutations, cellular escape pathways, and the influence of the bone marrow microenvironment.
View Article and Find Full Text PDFJ Hematol Oncol
November 2024
Georgia Cancer Center at Augusta University, 1410 Laney Walker Blvd., CN2222, Augusta, GA, 30912, USA.
Mutations in FMS-related receptor tyrosine kinase 3 (FLT3) are among the most common alterations in acute myeloid leukemia (AML), present in ≈30% of newly diagnosed AML cases. Internal tandem duplications (ITD) in FLT3 (FLT3-ITD) occur in ≈25% of newly diagnosed AML cases and are associated with unfavorable outcomes. Quizartinib (formerly AC220) is a novel, second-generation, highly potent, and selective type II FLT3 inhibitor.
View Article and Find Full Text PDFMyeloid malignancies carrying somatic DNMT3A mutations (DNMT3Amut) are usually resistant to standard therapy. DNMT3Amut leukemia cells accumulate toxic DNA double strand breaks (DSBs) and collapsed replication forks, rendering them dependent on DNA damage response (DDR). DNA polymerase theta (Polθ), a key element in Polθ-mediated DNA end-joining (TMEJ), is essential for survival and proliferation of DNMT3Amut leukemia cells.
View Article and Find Full Text PDFSci Rep
October 2024
Department of Medical Images, Hematology, and Oncology, Ribeirão Preto Medical School, University of São Paulo, 3900 Bandeirantes Avenue, Ribeirão Preto, São Paulo, 14040-900, Brazil.
Rinsho Ketsueki
October 2024
Department of Hematology and Oncology, Nagoya University Graduate School of Medicine.
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