Clinical implication and prognostic significance of FLT3-ITD and ASXL1 mutations in Egyptian AML patients: A single-center study

Therapeutic Targeting of FLT3 in Acute Myeloid Leukemia: Current Status and Novel Approaches

FMS-like tyrosine kinase 3 (FLT3) is mutated in approximately 30% of acute myeloid leukemia (AML) patients. The presence of FLT3-ITD (internal tandem duplication, 20-25%) mutation and, to a lesser extent, FLT3-TKD (tyrosine kinase domain, 5-10%) mutation is associated with poorer diagnosis and therapy response since the leukemic cells become hyperproliferative and resistant to apoptosis after continuous activation of FLT3 signaling. Targeting FLT3 has been the focus of many pre-clinical and clinical studies. Hence, many small-molecule FLT3 inhibitors (FLT3is) have been developed, some of which are approved such as midostaurin and gilteritinib to be used in different clinical settings, either in combination with chemotherapy or alone. However, many questions regarding the best treatment strategy remain to be answered. On the other hand, various FLT3-dependent and -independent resistance mechanisms could be evolved during FLT3i therapy which limit their clinical impact. Therefore, identifying molecular mechanisms of resistance and developing novel strategies to overcome this obstacle is a current interest in the field. In this review, recent studies of approved FLT3i and knowledge about major resistance mechanisms of clinically approved FLT3i's will be discussed together with novel treatment approaches such as designing novel FLT3i and dual FLT3i and combination strategies including approved FLT3i plus small-molecule agents targeting altered molecules in the resistant cells to abrogate resistance. Moreover, how to choose an appropriate FLT3i for the patients will be summarized based on what is currently known from available clinical data. In addition, strategies beyond FLT3i's including immunotherapeutics, small-molecule FLT3 degraders, and flavonoids will be summarized to highlight potential alternatives in FLT3-mutated AML therapy.

The role of circular RNA plasmacytoma variant translocation 1 as a biomarker for prognostication of acute myeloid leukemia

OBJECTIVE

Circular RNA plasmacytoma variant translocation 1 (circ-PVT1) has been reported to be an oncogene and serves as a prognostic biomarker in several solid cancers and hematological malignancies. However, no study has been performed on the tumorigenesis role of circ-PVT1 in acute myeloid leukemia (AML). Thus, this study aimed to evaluate the correlation of circ-PVT1 with disease risk, clinical characteristics, cytogenetics/molecular genetics, and prognosis of AML.

METHODS

A total of 68 de novo AML patients, 30 disease controls and 30 health donors were enrolled in this study. Circ-PVT1 expression in bone marrow (BM) was determined. Complete remission (CR) status after induction therapy, event-free survival (EFS) and overall survival (OS) were evaluated in AML patients.

RESULTS

Circ-PVT1 expression was different among AML patients, disease controls and health donors, which was highest in AML patients, followed by disease controls and lowest in health donors. Meanwhile, circ-PVT1 could distinguish AML patients from health donors and disease controls by receiver operating characteristic curve analysis. Furthermore, circ-PVT1 was correlated with BM blasts and FLT3-ITD mutation, but not other clinical features, such as French-American-Britain subtypes in AML patients. Moreover, circ-PVT1 expression was lower in AML patients with CR compared with those without CR. Besides, high circ-PVT1 expression was correlated with shorter EFS and OS in AML patients. After adjustment by multivariate Cox's regression analysis, higher circ-PVT1 expression was an independent factor in predicting shorter EFS and OS for AML patients.

CONCLUSION

Circ-PVT1 potentially serves as a biomarker for evaluating the prognosis of AML patients.