CD22ΔE12 is a driver lesion that we recently identified as the likely genetic cause for the drug resistance-associated activation of MAPK, PI3-K/m-TOR and WNT pathways in primary leukemia cells from relapsed as well as newly diagnosed high-risk BPL patients (including the BCR-ABL+/Ph+ subset)[7,8]. The gene discussed is MTOR; the disease is leukemia.