Allogeneic stem cell transplantation in adult Ph-like acute lymphoblastic leukemia. Results from two consecutive GIMEMA protocols

BCR::ABL1-like acute lymphoblastic leukemia, also referred to as Ph-like ALL, is a heterogeneous subtype of B-cell precursor ALL (BCP-ALL) with a gene-expression profile resembling BCR::ABL1-positive ALL, despite lacking the BCR::ABL1 fusion. It is enriched for kinase-activating lesions and is associated with adverse prognosis in pediatric and adult cohorts [ 1 , 2 , 3 ]. In adults, its incidence increases with age and may reach approximately 30% in older patients [ 4 ]. Although the Ph-like signature can identify patients with potentially targetable lesions, routine detection remains challenging because gene-expression profiling and RNA sequencing are not universally available. To facilitate the identification of Ph-like cases, Chiaretti et al. developed the “BCR/ABL1-like predictor”, a quantitative real-time PCR-based tool relying on the expression levels of 10 genes and showing high sensitivity and specificity as a surrogate diagnostic approach [ 5 ]. The optimal post-remission strategy for adult Ph-like ALL remains incompletely defined. In particular, although allogeneic hematopoietic stem cell transplantation (alloHSCT) is an effective consolidation strategy for high-risk or chemoresistant ALL, its specific role in Ph-like ALL has not been conclusively established.