BCS1L and acute lymphoblastic leukemia: In the present study, we found that partner genes such as MLL-AF4, MLL-PTD and MLL-ENL were more common in MLL-r positive ALL, and further comparison of EFS and OS among the three groups showed statistically significant differences, indicating that MLL-AF4 positive ALL had the worst prognosis, and the results also indicated that the MLL fusion gene type (MLL-AF4) as an independent risk prognostic factor.