Case Report: amplification in two adult patients with B-cell acute lymphoblastic leukemia.

The gene, located at chromosome band 11q23, encodes a lysine methyltransferase essential for hematopoietic gene regulation. While rearrangements are common in acute myeloid leukemia (AML) and B-cell acute lymphoblastic leukemia (B-ALL), amplification is rare, occurring in ~1% of AML cases and even less frequently in B-ALL. Given its rarity, understanding amplification in B-ALL is crucial for improving diagnostics and therapy. We report two adult B-ALL cases with amplification. Patient 1, a 58-year-old male, had amplification (6~18 copies in 68.5% of bone marrow cells), a complex karyotype, and a pathogenic variant (c.524G>A, p.Arg175His). He underwent induction chemotherapy but passed away after two months due to complications. Patient 2, a 66-year-old female, had amplification (8~11 copies in 87.5% of peripheral blood cells) and rearrangement, representing the first reported case of Ph-like B-ALL with amplification in an adult. She deteriorated rapidly and died within four days. In addition to these two cases from our cohort, we review nine published cases with amplification in B-ALL, which showed frequent alterations, emphasizing the clinical and genetic characteristics of this aggressive leukemia subtype. These cases highlight the high-risk nature of -amplified B-ALL, particularly in older adults, where prognosis is poor and linked to variants or rearrangement. Our review underscores the need for genetic profiling to improve risk stratification and treatment. Given the limited documented cases, further research is essential to develop better therapeutic strategies for -amplified B-ALL.