TCF3 and acute lymphoblastic leukemia: Among reported BL-like ALL cases, only t(1;19) is repeatedly found in gene analyses, indicating that it plays a critical role in ALL resembling BL.3 The phenotype is also associated with approximately 85% event-free 5-year survival rates.7,8 By contrast, childhood ALL harboring t(17;19) (q22;p13) translocation and TCF3-HLF fusion is extremely rare (< 0.5% of cases) but very aggressive and associated with a poor outcome.8-10