Philadelphia-Like Acute Lymphoblastic Leukemia: A Systematic Review

Philadelphia-like (Ph-like) acute lymphoblastic leukemia (ALL) is a subgroup of B-cell precursor ALL (BCP-ALL) with a gene expression profile analogous to Philadelphia-positive ALL and recurrent IKAROS Family Zinc Finger 1 (IKZF1) gene deletion despite lacking BCR-ABL1 (Breakpoint cluster region-ABL protooncogene) translocation. Although recognized to occur at all ages, the proportion of cases among BCP-ALL varies (< 10% in children and up to 30% in adolescents). In all age groups, males are more commonly affected. Generally, Ph-like ALL is associated with adverse clinical features and an increased risk of treatment failure with conventional approaches. Genetic alterations such as aberrant expression, point mutations, or fusion translocations lead to activation of cytokine receptors and signaling kinases, which affect the ABL1 (ABL class fusion) or Janus Kinase (JAK) signaling pathways. Several clinical trials are being conducted to understand whether specific tyrosine kinase inhibitor therapy can improve cure rates. This review summarizes the current literature available about this entity.