Introduction: B-cell precursor acute lymphoblastic leukemia (B-ALL) is defined by the expression of B-lineage antigens by malignant precursor lymphoid cells while acute leukaemia of ambiguous lineage (ALAL) expresses combinations of immunophenotypic markers that do not permit definitive lineage assignment. 1 VDJ recombination of immunoglobulin heavy chain DNA sequences, leading to antigen receptor diversity, is a hallmark of B-cell development. 2 This unique sequence can serve as a clonal marker for malignant cells. 2 Molecular abnormalities also play a key role in subclassification of acute leukaemias. 1,3
Watson et al. (2026) studied this question.