[Analysis of Bone Marrow and Peripheral Blood Cytological Characteristics and Prognostic Research in FLT3-ITD mutated...

To investigate the bone marrow and peripheral blood cytological characteristics and prognosis in acute myeloid leukemia (AML) with FLT3-ITD mutation.

A total of 106 newly diagnosed AML patients who were hospitalized in the First Affiliated Hospital of Xi'an JiaoTong University from January 2021 to December 2023 were collected, and divided into mutation group and non-mutation group according to the results of high-throughput sequencing of bone marrow specimens. The cytological characteristics of bone marrow smears and peripheral blood smears of patients in the two groups were analyzed at the time of initial diagnosis. The differences in the degree of hyperplasia, the proportion of leukemic cells, and the erythroblasts and megakaryocytes were compared between the two groups. What's more, the relationship between FLT3-ITD mutation status and characteristics of bone marrow and peripheral blood cells was analyzed.

AML patients with FLT3-ITD mutation accounted for 24.53% of the hospitalized AML patients during the same period. Patients with peripheral blood leukocyte counts >30×10⁹/L accounted for 53%, and >100×10⁹/L accounted for 15% in FLT3-ITD mutation group. Compared with non-mutation group, the peripheral blood leukocyte count was significantly higher in the mutation group ( P <0.001), and the degree of hemoglobin decline was milder (P <0.05). The level of platelet was not significantly different between the two groups (P >0.05). The highest proportion of FAB subtypes were M2a and M5a in mutation group, which accounted for 38% and 27%, respectively. The proportion of extreme hyperplasia of bone marrow in the mutation group was 38.46%, which was higher than 23.75% in the non-mutation group. The proportion of peripheral blood and bone marrow leukemic cells in patients with high-frequency mutation were significantly higher than those in patients with low-frequency mutation (both P <0.01). The complete remission (CR) rate after the first induction chemotherapy was 38.46% and 65.00% in the mutation group and non-mutation group, respectively, and the CR rate after 2 courses of induction chemotherapy was 50.00% and 73.75%, respectively.

The FLT3-ITD mutation results in high proliferation and rapid progression of the bone marrow feature in AML patients, with less suppression of normal erythropoiesis. Increased mutation frequency is accompanied by increased leukemic tumor burden in the bone marrow and circulation, and patients with FLT3-ITD mutation have a low response rate to early induction therapy.