CPT® Code 81245

FLT3 (fms-related tyrosine kinase 3) (eg, acute myeloid leukemia), gene analysis; internal tandem duplication (ITD) variants (ie, exons 14, 15)

Molecular genetic testing is performed to identify a specific mutation of the FLT3 (fms-related tyrosine kinase 3) gene associated with acute myeloid leukemia (AML). This gene analysis focuses on internal tandem duplication (ITD) variants found in exons 14 and 15 of the FLT3 gene. Genetic testing for this mutation is considered the standard of care for all patients diagnosed with AML, as it plays a crucial role in determining the appropriate therapeutic approach. The presence or absence of the FLT3 gene mutation can significantly influence treatment decisions, helping to predict the potential benefits of specific therapies and the associated risks of recurrence or disease progression. Notably, the FLT3 mutation is present in at least 25% of all patients diagnosed with AML, although its presence does not necessarily correlate with a poor cure rate. AML is recognized as the most common type of acute leukemia, predominantly affecting men over the age of 65, while it is rarely diagnosed in individuals under the age of 40. The FLT3 gene encodes a class 3 tyrosine kinase receptor that is integral to the regulation of hematopoiesis. This receptor is activated when the FLT3 ligand binds to its extracellular domain, leading to the formation of homodimers in the plasma membrane. This process triggers autophosphorylation of the receptor, which continues to activate cytoplasmic effector molecules involved in the pathways of apoptosis, proliferation, and differentiation of hematopoietic cells within the bone marrow. Mutations in the FLT3 gene can lead to the development of acute myeloid leukemia as well as acute lymphoblastic leukemia.