Allogeneic hematopoietic stem cell transplantation overcomes the poor prognosis in MLL-rearranged solid tumor therapy related-acute myeloid leukemia

MLL rearrangement is very common in solid tumor therapy-related acute myeloid leukemia (t-AML). To investigated the prognosis of solid tumor MLL t-AML, 157 patients were divided into 3 groups: non-MLL t-AML (n=41), MLL t-AML (n=18) and MLL de novo AML (n=98). Of the 150 patients underwent anti-leukemia therapy, the complete remission (CR) was similar in MLL t-AML, non-MLL t-AML and MLL de novo AML (P=0.251). 3-years overall survival (OS) was 37.5%, 21.5% and 20.4% (P=0.046), and leukemia-free survival (LFS) was 28.0%, 32.2% and 22.7% (P=0.031), and the incidence of relapse was 30.0%, 50.4% and 53.5% (P=0.382), respectively, in the three groups. Multivariate analysis revealed that MLL t-AML was a risk factor while allo-HSCT was a protective factor for OS, LFS, and relapse (P<0.001, P<0.001 and P=0.005) (P=0.002, P<0.001 and P<0.001, respectively). The 3-years OS was 0%, 17.9% and 2.3% (P=0.038), and LFS was 0%, 23.1% and 3.3% (P=0.017), and relapse was 100%, 53.1% and 74.4% (P=0.001), respectively, among three groups in patients undergoing chemotherapy alone, while OS was 64.3%, 52.7% and 40.7% (P=0.713), LFS was 60.0%, 48.8% and 37.0% (P=0.934), and relapse was 25.0%, 47.4% and 47.5% (P=0.872), respectively, among these groups in patients undergoing allo-HSCT. Intriguingly, MLL t-AML was no longer risk factor for relapse and LFS (P=0.882 and P=0.484, respectively), and it became a favorable factor for OS (P=0.011) in patients undergoing allo-HSCT. In conclusion, MLL t-AML had poor prognosis compared with non-MLL t-AML and MLL de novo AML, but allo-HSCT might overcome the poor prognosis of MLL t-AML.