The ALL1/AF4 fusion transcript, originating from the t(4;11) translocation, was detected in 24 patients (36.4%), and the BCR/ABL chimeric product was found in 6 patients (9%), while the remaining 36 cases (54.6%) were ALL1/AF4-BCR/ABL-negative.     ///    Clinico-biologic features and treatment outcome of adult pro-B-ALL patients enrolled in the GIMEMA 0496 study: absence of the ALL1/AF4 and of the BCR/ABL fusion genes correlates with a significantly better clinical outcome..     ///    "Our data demonstrate that in adult pro-B-ALL a distinction should be made between pro-B-ALL cases with and without the ALL1/AF4 or the BCR/ABL chimeric genes, since the absence of both of these fusion genes correlates with a significantly better clinical outcome after intensive polychemotherapy treatment without hematopoietic stem cell transplantation.. "    ///    "By contrast, CD13 and CD33 molecules were detected, respectively, in 3 of 6 and in 14 of 33 cases of the BCR/ABL-positive patient group, and in 2 of 6 and 9 of 35 cases of the ALL1/AF4-BCR/ABL-negative patient group. "    ///    "A white blood cell (WBC) count higher than 50 x 109/L was found in 13 of 24, 2 of 6, and 6 of 36 of the ALL1/AF4-positive, BCR/ABL-positive, and ALL1/AF4-BCR/AB-negative patients, respectively (P =.007). "    ///    "By contrast, comparing patients with or without the ALL1/AF4 gene the probability of remaining in continuous complete remission (CCR) at 3.5 years was 16% and 49.8%, respectively (P =.005). "    ///    None of the 24 ALL1/AF4-positive patients coexpressed the CD13 and/or CD33 myeloid antigens. 