The genomic landscape of juvenile myelomonocytic leukemia

Area of Science:

• Pediatric Hematology Oncology
• Cancer Genomics
• Molecular Biology

Background:

• Juvenile myelomonocytic leukemia (JMML) is a childhood myeloproliferative neoplasm with a poor prognosis.
• Existing treatments lack risk stratification, hindering personalized therapy and identification of candidates for experimental treatments.
• The RAS-MAPK pathway is implicated, but other molecular targets remain largely unexplored.

Purpose of the Study:

• To perform comprehensive genomic characterization of serial JMML samples from diagnosis to relapse and transformation.
• To identify novel mutations and molecular pathways beyond RAS-MAPK in JMML.
• To establish a basis for improved risk stratification and novel therapeutic strategies in JMML.

Main Methods:

• Whole-exome sequencing of diagnostic, relapse, and transformed acute myeloid leukemia samples from JMML patients.
• Analysis of mutation spectrum, including genes in signal transduction, splicing, Polycomb repressive complex 2 (PRC2), and transcription.
• Correlation of genomic findings with clinical outcomes and disease progression.

Main Results:

• Identification of recurrent mutations in genes regulating signal transduction, splicing, PRC2, and transcription.
• Discovery of a broader mutational landscape in JMML beyond known RAS-MAPK pathway alterations.
• Demonstration that the number of somatic alterations at diagnosis is a significant determinant of patient outcome.

Conclusions:

• Genomic characterization of serial JMML samples reveals novel mutations and pathways.
• The total number of somatic alterations at diagnosis is a critical factor for predicting JMML patient outcomes.
• These findings provide a foundation for developing improved risk stratification algorithms and targeted therapies for JMML.