T/myeloid mixed phenotype acute leukaemia harbouring TLX3::BCL11B with TLX3 activation.

T/myeloid mixed phenotype acute leukaemia (MPAL) is a rare aggressive acute leukaemia with poorly understood pathogenesis. Herein, we report two cases of T/myeloid MPAL harbouring BCL11B-associated structural variants that activate TLX3 (TLX3::BCL11B-TLX3-activation) by genome sequencing and transcriptomic analyses. Both patients were young males with extramedullary involvement. Cooperative gene alterations characteristic of T/myeloid MPAL and T-lymphoblastic leukaemia (T-ALL) were detected. Both patients achieved initial remission following lineage-matched ALL-based therapy with one patient requiring a lineage-switched myeloid-based therapy. Our study is the first to demonstrate the clinicopathological and genomic features of TLX3::BCL11B-TLX3-activated T/myeloid MPAL and provide insights into leukaemogenesis.

Risk factors for readmission after initial diagnosis in children with acute lymphoblastic leukemia.

BACKGROUND: Specific hospital discharge criteria following the initial diagnosis of children with acute lymphoblastic leukemia (ALL) have not been reported. This retrospective cohort study was designed to identify risk factors for readmission during induction therapy, to assist with development of discharge guidelines. PROCEDURE: We reviewed the records of 142 consecutive children with newly diagnosed B-precursor ALL and found 129 eligible patients. Chi square, t-test, and multivariate logistic regression analysis were used to compare differences in absolute neutrophil count (ANC), NCI risk status, age, type of corticosteroid administered, and other potential risk factors for readmission during induction therapy. RESULTS: ANC at initial hospital discharge was the only significant predictor of readmission for fever during induction therapy (P = 0.006) by multivariate analysis. Specifically an ANC 200/mm(3), in a clinically stable patient, is associated with minimal risk of readmission during induction therapy following the initial diagnosis of ALL.

Novel r(2)(p25q31) cytogenetic abnormality in a pediatric patient with acute leukemia of ambiguous lineage.

We describe a case of acute leukemia of ambiguous lineage with a novel cytogenetic abnormality. A 1-year-old boy presented with abnormal complete blood count findings, and was found to have blasts and mild dysgranulopoiesis. The blasts showed immunophenotypic evidence of myeloid and T-lineage differentiation. Subsequent cytogenetic analysis showed r(2)(p25q31) as the sole stem line cytogenetic defect with clonal evolution. While cytogenetic abnormalities can have a critical role in the classification and prognostication of acute lymphoblastic and acute myeloid leukemia, the significance of cytogenetic abnormalities in acute leukemia of ambiguous lineage remains unclear. This finding has not been reported previously to the best of our knowledge.