# Somatic mutations and outcomes in chronic myeloid leukemia adolescent and young adults compared to children, adults, and BCR::ABL1-positive acute lymphoblastic leukemia

## TL;DR

This study compares genetic mutations and treatment outcomes in young adults with chronic myeloid leukemia to children, adults, and those with a related blood cancer.

## Contribution

The study reveals distinct mutation patterns and treatment responses in adolescent and young adult leukemia patients.

## Key findings

- AYAs with CML-CP had higher cancer-related gene mutation rates than adults or children.
- ASXL1 mutations were linked to worse survival in AYAs and adults but not to increased BCR::ABL1 mutations during treatment.
- Nilotinib improved outcomes for AYAs with ASXL1 mutations, suggesting the benefit of higher-generation TKIs.

## Abstract

Adolescent and young adults (AYAs) with chronic myeloid leukemia in chronic phase (CML-CP) reportedly respond worse to tyrosine kinase inhibitors (TKIs) than adults, potentially due to additional genetic abnormalities, including mutations in cancer-related genes (CRGs). This real-life study compared mutation profiles and their impact on outcomes in 80 AYA, 97 adult, and 16 pediatric CML-CP patients, alongside 81 BCR::ABL1-positive acute lymphoblastic leukemia (Ph+ ALL) patients. CRG mutations were more frequent in AYAs (25.0%) than in adults (19.6%) or children (12.5%). AYAs with Ph+ ALL exhibited higher mutational frequencies (53.3%) compared to children (26.7%) and adults (38.9%). At diagnosis, mutations in ASXL1, DNMT3A, and TET2 dominated in CML-CP and RUNX1, IKZF1, and BCR::ABL1 in Ph+ ALL. ASXL1 mutations correlated with reduced progression-free survival (PFS) in AYAs and adults. Unlike adults, AYAs showed no increase in BCR::ABL1 kinase domain mutations during TKI therapy. Nilotinib improved PFS in AYAs with ASXL1 mutations, highlighting the efficacy of higher-generation TKIs. ASXL1 mutations also impaired erythropoiesis, warranting further validation. Despite a higher mutational burden, AYAs did not exhibit worse prognoses than adults. Lower mutation rates at follow-up suggest potential impact of nilotinib. Mutation profiling and optimized TKI use are crucial to mitigate progression risks in CRG-mutated patients.