EFS for patients with t(4;11) negative/MLL-AF4⁺ ALL. Percentage of patients surviving event-free was compared for 15MLL-AF4⁺ patients who lacked cytogenetically detectable t(4;11) and 97 patients who showed no evidence for MLL-AF4, BCR-ABL, or E2A-PBX1fusion transcripts. (Inset) Number of patients in follow-up at indicated times.