[Acute leukemia of infants and neonates]

Area of Science:

• Hematology
• Pediatric Oncology
• Molecular Biology
• Genetics

Background:

• Leukemias in infants (<1 year) exhibit aggressive clinical behavior and distinct biological features.
• Infant acute lymphoblastic leukemia (ALL) remains challenging to treat compared to other pediatric ALL.
• Frequent KMT2A (MLL) gene rearrangements, especially KMT2A-AFF1 (MLL-AF4) fusion, are hallmarks of poor prognosis in infant ALL.

Purpose of the Study:

• To summarize recent clinical, cytogenetic, and molecular findings in neonatal and infant leukemias.
• To highlight the unique characteristics and challenges in treating leukemia in this young population.
• To underscore the need for international collaboration to advance treatment strategies.

Main Methods:

• Review of recently reported clinical data.
• Analysis of cytogenetic abnormalities, including specific translocations like t(1;22) and t(8;16).
• Summary of molecular biology findings, focusing on gene rearrangements such as KMT2A (MLL).

Main Results:

• Infant leukemias frequently involve KMT2A (MLL) gene rearrangements, with KMT2A-AFF1 (MLL-AF4) indicating poor prognosis.
• Specific cytogenetic abnormalities like RBM15-MKL1 and KAT6A-CREBBP (MOZ-CBP) are noted in infant acute myeloblastic leukemia.
• While many neonatal leukemias are refractory, spontaneous remissions can occur, particularly with t(8;16).

Conclusions:

• Neonatal and infant leukemias present unique biological and clinical challenges requiring specialized understanding.
• Understanding specific genetic alterations (e.g., KMT2A fusions, t(8;16)) is crucial for prognosis and treatment.
• International collaborative studies are essential for improving therapeutic outcomes in this rare disease.