Classifying AML patients with inv(16) into high-risk and low-risk relapsed patients based on peritransplantation minimal residual disease determined by CBFβ/MYH11 gene expression

Ninety acute myeloid leukemia (AML) patients with inv(16) were monitored CBFβ/MYH11 transcript around allogeneic hematopoietic stem cell transplantation (allo-HSCT). A total of 23 patients received HLA-matched sibling donor transplantation (MSDT) and 67 patients received unmanipulated haploidentical hematopoietic stem cell transplantation (haplo-HSCT) were analyzed in this study. Patients were divided into four groups based on CBFβ/MYH11 expression prior to transplantation (pre-MRD): with negative (group 1)/positive (group 2) pre-MRD before MSDT; with negative (group 3)/positive (group 4) pre-MRD before haplo-HSCT. The results showed that patients in group 2 had the highest cumulative incidence of relapse (2-year CIR, 40.7%), the lowest leukemia-free survival (2-year LFS, 50.8%), and overall survival (2-year OS, 62.5%). The other three groups of patients had comparable outcomes. The patients were also classified into the other three groups according to CBFβ/MYH11 value of + 1 month after transplantation: group 5: pre- and post-transplant MRD were both negative; group 6: the value of post-transplant MRD was lower than 0.2%; group 7: the value of post-transplant MRD was higher than 0.2%. Group 7 had the highest CIR and the lowest LFS. These results indicated that AML patients with inv(16) were able to be separated into high-risk and low-risk relapse groups based on peritransplant MRD determined by RQ-PCR-based CBFβ/MYH11. Haplo-HSCT might overcome the negative impact of pre-MRD on patient outcomes compared to MSDT.