Genetic landscape of acute myeloid leukemias with leukocytosis

Background. Tumor cell proliferation in acute myeloid leukemia (AML) may manifest with high leukocyte counts. In our work, we evaluate the association of high leukocyte counts with individual mutations, as well as their total contribution to the development of leukocytosis in AML. The results obtained should improve our understanding of pathogenic mechanisms leading to the leukocytosis in AML. Aim. To study the genetic landscape of AML with leukocytosis. Materials and methods. The laboratory data of 214 AML patients admitted to the National Medical Research Center for Hematology (Moscow) from 2010 to 2022 were retrospectively examined. Real-time PCR, capillary electrophoresis and NGS (next generation sequencing) methods were used to detect mutations of FLT3, NPM1, CEBPA, IDH1/2, DNMT3A, TET2 genes, and CBFB::MYH11, RUNX1::RUNX1T1 chimeric gene transcripts. Results. Mutations of the FLT3 gene (odds ratio 5.45; p < 0.0001), inv(16)/ CBFB::MYH11 (odds ratio 10.03; p = 0.0009) are most associated with leukocyte counts higher than 30 × 10 9 / L in the debut of AML. Translocation t(8;21) /RUNX1::RUNX1T1 and adverse cytogenetic aberrations, such as -5/del(5q); -7 / del(7q); -17 / abn(17p), complex and monosomic karyotype were significantly associated with leukocyte counts lower than 30 × 10 9 / L at the time of disease manifestation (p < 0.0001). In the group of patients with intermediate cytogenetic risk bearing only IDH1/2, DNMT3A , and TET2 gene mutations, leukocyte counts at AML debut were significantly lower, whereas the most pronounced leukocytosis was observed in patients with a combination of driver mutations with IDH1/2, DNMT3A , and TET 2 gene mutations or FLT3, NPM1 , and CEBPA gene mutations. Conclusion. In addition to the individual effect of certain genetic lesions and cytogenetic aberrations on the proliferative potential of tumor cells, there is a total contribution of various types of genetic events to the development of leukocytosis in AML. High leukocyte counts at the time of AML manifestation in patients with intermediate cytogenetic risk can serve as an indirect marker of the presence of a large number of genetic aberrations with a combination of IDH1/2, DNMT3A , and TET2 gene mutations or FLT3, NPM1 , and CEBPA gene mutations.