Overall survival probability in MLL rearrangement-positive versus MLL rearrangement-negative CD10^- pre-B ALL. Overall survival probability in 7 patients with MLL rearrangement-negative CD10^- pre-B ALL (0.34 ± 0.20 SE; top broken line) and in 33 with MLL rearrangement-positive CD10^- pre-B ALL (0.12 ± 0.06 SE; bottom solid line) after treatment in the GMALL studies 04/89, 05/93, 06/00, and 07/03. Median follow-up was 354 days for MLL rearrangement-negative versus 278 days for MLL rearrangement-positive patients.