Treatment Approaches for Philadelphia Chromosome-Like Acute Lymphoblastic Leukemia

Philadelphia chromosome-like acute lymphoblastic leukemia (ALL) is a group of diseases that possess similar gene expression patterns to those of Philadelphia chromosome-positive ALL, but lack the BCR-ABL1 gene rearrangement and exhibit diverse genetic characteristics. These cases are associated with a poorer prognosis than that of other B-cell ALL cases and require novel therapeutic approaches. Philadelphia chromosome-like ALL can be categorized into ABL-activated, Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway-altered, and other subtypes based on genetic alterations. For the ABL-activated subtype, treatment with ABL-directed tyrosine kinase inhibitors may improve outcomes, whereas JAK-directed tyrosine kinase inhibitors have been proposed as a combination therapy for patients with JAK-STAT pathway mutations. In this review, we discuss treatment approaches for each subtype of Philadelphia chromosome-like ALL.