As aforementioned, ABL-class fusion positive ALL is a high-risk ALL subtype associated with unfavorable outcomes when treated with conventional risk-adapted multi-agent chemotherapy [84], which is likely to benefit from the addition of TKIs such as imatinib and dasatinib as suggested by recent anecdotal evidence and retrospective studies [84,85,86]. This evidence concerns the gene ABL1 and acute lymphoblastic leukemia.