Foreword

Leukemia is a relatively rare form of cancer, accounting for roughly 1% of new cancer diagnoses each year. Acute myeloid leukemia (AML) is the deadliest and most common type of leukemia, making up approximately one-third of all leukemia diagnoses. At just over 11,000 deaths a year, AML accounts for nearly half the number of annual leukemia deaths (23,100). 1 In broad terms, AML can be further categorized based on genetic aberrations, clinical manifestations, and patient prior treatment. The World Health Organization (WHO) divides AML into no fewer than two dozen subtypes with differing prognostic factors. 2 Distinct leukemia molecular subtypes are identifiable by immunophenotype, chromosomal mutation, and gene mutation.

The most common AML mutation is the FMS-like tyrosine kinase 3 (FLT3) gene, which is detected in approximately 30% of AML cases. Of FLT3 mutation subtypes, internal tandem duplication (ITD) is the most common, with FLT3-ITDs found in 25% of all AML cases. 3 According to the National Comprehensive Cancer Network (NCCN) and European LeukemiaNet (ELN), the FLT3-ITD mutation is associated with high risk and poor outcome. 3 The array of leukemic subtypes and prevalence of FLT3 mutations in AML highlight the importance of genetic profiling at the time of diagnosis for comprehensive prognostics and for identifying targetable oncogenic pathways. As FLT3 inhibitors entered the treatment landscape, FLT3 profiling at diagnosis shifted from being purely prognostic to being predictive of patient response and overall survival. 4

With their distinct immunophenotypic profiles, AML and acute lymphoblastic leukemia (ALL) are distinguished through flow cytometry, which is performed for 99.1% of all AML patients. Karyotyping, which 98% of AML patients receive, further distinguishes clonal cytogenetic abnormalities as subtypes of AML. 5,6 A 2016 survey found that only 51% of AML patients were tested for FLT3 genetic mutations, ostensibly leaving a significant portion of AML patients with a gap in treatment options. 5

However, that gap is quickly closing.

Anna Love Editor

Dr. Anna Love earned her bachelor’s degree in English in 2009, before returning to school in 2011 for post-baccalaureate studies in science. In 2014, Dr. Love completed her master’s degree in biomedical sciences at William Carey College of Medicine. After which, Dr. Love pursued a Ph.D. in molecular biosciences at Middle Tennessee State University with a focus on developmental and cell biology. Dr. Love currently works as a research fellow at Vanderbilt University Medical Center in the Department of Medicine.