Would be fascinating if they could harvest healthy host progenitor cells, destroy the leukemic cells with another persons's engineered off-the-shelf graft which

Would be fascinating if they could harvest healthy host progenitor cells, destroy the leukemic cells with another persons's engineered off-the-shelf graft which has a couple of chemically (e.g. tetracycline) inducible kill-switches, and wait until the graft destroys the cancer to turn on the kill switch and replant the patient's stored cells. This could prevent lifelong graft versus host disease, but the risk of death/complications from an additional retransplant or the reemergence of dormant cancer cells may be too great to make it worth the risk.