The lack of association between pretreatment TKI-resistant ABL1 mutations and subsequent relapse observed in our study suggests ponatinib-containing regimens exert superior activity in newly diagnosed Ph + ALL primarily by preventing later outgrowth of random, background levels of resistance mutations, rather than suppressing meaningfully subclonal, pretreatment ABL1 mutations. The gene discussed is ABL1; the disease is acute lymphoblastic leukemia.