Recently, the T681I gatekeeper mutation has been demonstrated to be the most common resistant mutation in EBF1-PDGFRB Ph-like ALL to both imatinib and dasatinib in in vitro screens and it was associated with a trend towards increased risk of relapse in patients harboring T681I subclones at diagnosis compared to T681I-negative patients [50]. The gene discussed is PDGFRB; the disease is acute lymphoblastic leukemia.