Kaplan-Meier survival plot of mice receiving bone marrow cells transduced by distinct FGFR3 TDII constructs. Mice that received transplants of various FGFR3 TDII constructs (except FF4F) succumbed to a fatal pre–B-cell lymphoma. None of 12 mice that received transplants of FF4F developed any disease by 180 days after transplantation when the experiment was terminated.