Biomarcador FLT3-ITD: perspectivas y retos / FLT3-ITD biomarker: perspectives and challenges

Introducción: Las mutaciones del gen que codifica para el factor de la tirosina quinasa 3 (FLT3) son de especial importancia en la leucemia mieloide aguda debido a que sirven de guía para la confirmación del diagnóstico, la estimación del pronóstico y la toma de decisiones terapéuticas. Entre las alteraciones más importantes está la duplicación interna en tándem (FLT3-ITD). Objetivo: Exponer los aspectos más relevantes respecto al biomarcador FLT3-ITD en el contexto de la leucemia mieloide aguda. Métodos: Se realizó una búsqueda de artículos científicos actualizados en los idiomas inglés y español, en PubMed, EMBASE, Google Scholar y SciELO. Se seleccionaron artículos publicados en los últimos cinco años. Se revisaron los aspectos más relevantes sobre el biomarcador en el contexto de la leucemia mieloide aguda, su base biológica, el impacto del tamaño de los fragmentos y la carga alélica en la estimación del pronóstico de los pacientes, las nuevas estrategias terapéuticas y los retos en cuanto a los métodos de laboratorio para su diagnóstico. Análisis y síntesis de la información: Más allá de la positividad o no de dicho biomarcador, el tamaño de la duplicación interna en tándem, así como la carga alélica -determinada por la razón alelo mutado/alelo salvaje-, podrían tener un gran impacto en el pronóstico. Sin embargo, persisten diferencias en los criterios para establecer los algoritmos de predicción del riesgo, el punto de corte a utilizar como referencia y el protocolo de laboratorio específico para un estudio más detallado del biomarcador. Conclusiones: La comunidad científica necesita seguir trabajando en el esclarecimiento de la utilidad práctica de estos parámetros, validándolos en series amplias y diversas epidemiológicamente. Se debe determinar el punto de corte exacto para comparar la razón y estandarizar los métodos de laboratorio más adecuados y factibles para su estudio(AU)

ABSTRACT Introduction: Mutations in the tyrosine kinase 3 gene (FLT3) are of special importance in acute myeloid leukemia because they serve as a guide to confirm the diagnosis, estimate the prognosis, and make therapeutic decisions in the patient. Internal tandem duplication (FLT3-ITD) is the most important alteration of this gene. Objective: To present the most relevant aspects regarding the FLT3-ITD biomarker in the context of acute myeloid leukemia. Methods: a search was carried out for updated scientific articles, in English and Spanish, in PubMed, EMBASE, Google Scholar and SciELO. Articles published in the last five years were selected. The most relevant aspects of the biomarker in the context of acute myeloid leukemia, its biological basis, the impact of the size of the fragments and the allelic load in the estimation of the prognosis of the patients, the new therapeutic strategies and the challenges in regarding the laboratory methods for its diagnosis. Information analysis and synthesis: Beyond the biomarker positivity or not, the size of the ITD, as well as the allelic ratio determined by the mutated allele / wild-type allele, could have a great impact on the prognosis of patients. However, differences persist in the criteria for establishing risk prediction algorithms, the cut-off point to be used as a reference, and the specific laboratory protocol for a more detailed study of the biomarker. Conclusions: The scientific community needs to continue working to clarify the practical utility of these parameters, validating them in broad and epidemiologically diverse series. The exact cut-off point should be determined as a reference to compare the relationship and standardize the most suitable and feasible laboratory methods for its study(AU)

Early mortality in acute promyelocytic leukemia: Potential predictors.

Acute promyelocytic leukemia (APL) is a rare leukemia characterized by the balanced reciprocal translocation between the promyelocytic leukemia gene on chromosome 15 and the retinoic acid receptor α (RARα) gene on chromosome 17, and accounts for 10-15% of newly diagnosed acute myeloid leukemia each year. The combined use of all-trans retinoic acid and arsenic trioxide (ATO) as primary therapy has markedly improved the survival rate of patients with APL. Mortality in the first 30 days following therapy remains a major contribution to treatment failure. In the present study, published data was reviewed with a focus on the factors associated with early mortality. When treated with ATO as a primary treatment, the fms-like tyrosine kinase-internal tandem deletion has no impact on early mortality. Low lymphoid enhancer binding factor-1 expression may be a reliable marker for early mortality and the target of therapy if it could be proven by further studies. Cluster of differentiation (CD)56+ and CD34+/CD2+ may be candidates to select high-risk patients. The risk of early mortality in APL still cannot be predicted via the cell surface makers, despite multiple studies on their prognostic significance. Typically, a complex translocation did not alter the survival rate in patients with APL; however, if an abnormal karyotype [e.g., Ide(17), ZBTB16/RARα and STAT5B/RARα] appeared singularly or as part of a complex mutation, there is a high possibility of early mortality if clinicians are unable to identify or monitor it.

Investigational FMS-like tyrosine kinase 3 inhibitors in treatment of acute myeloid leukemia.

INTRODUCTION: Outcomes for the majority of patients with acute myeloid leukemia (AML) remain poor. Over the past decade, significant progress has been made in the understanding of the cytogenetic and molecular determinants of AML pathogenesis. One such advance is the identification of recurring mutations in the FMS-like tyrosine kinase 3 gene (FLT3). Currently, this marker, which appears in approximately one-third of all AML patients, not only signifies a poorer prognosis but also identifies an important target for therapy. FLT3 inhibitors have now undergone clinical evaluation in Phase I, II and III clinical trials, as both single agents and in combination with chemotherapeutics. Unfortunately, to date, none of the FLT3 inhibitors have gained FDA approval for the treatment of patients with AML. Yet, several promising FLT3 inhibitors are being evaluated in all phases of drug development. AREAS COVERED: This review aims to highlight the agents furthest along in their development. It also focuses on those FLT3 inhibitors that are being evaluated in combination with other anti-leukemia agents. EXPERT OPINION: The authors believe that the field of research for FLT3 inhibitors remains promising, despite the historically poor prognosis of this subgroup of patients with AML. The most promising areas of research will likely be the elucidation of the mechanisms of resistance to FLT3 inhibitors, and development of potent FLT3 inhibitors alone or in combination with hypomethylating agents, cytotoxic chemotherapy or with other targeted agents.