ABCG2, Cytogenetics, and Age Predict Relapse after Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia in Complete Remission

• ABGG2 overexpression in acute myeloid leukemia is associated with poor response to chemotherapy and increased relapse risk
• Few data are available in patients receiving allogeneic stem cell transplantation in remission
• We analyzed 105 patients with acute myeloid leukemia undergoing stem cell transplantation in complete remission
• ABCG2 and unfavorable cytogenetics were associated with shorter leukemia-free survival
• ABCG2, cytogenetics, and age (>50 years) were predictive of a higher incidence of relapse (3-year cumulative incidence of relapse of 0%, 12%, and 47% in patients with no, 1, or ≥ 2 risk factors; P = .00005)

Recent studies have shown that ABGG2 protein overexpression in acute myeloid leukemia (AML) may be associated with poor response to therapy and increased relapse risk. Few data are available in patients with AML undergoing allogeneic stem cell transplantation (SCT), particularly when in complete remission (CR). We analyzed 105 patients with AML who underwent allogeneic SCT in CR evaluating the role of ABCG2 and other pretransplantation features on subsequent transplantation outcomes. Factors negatively associated with leukemia-free survival (LFS) were unfavorable cytogenetics (3-year LFS 48% versus 80%, P = .0035) and ABCG2 positivity (65% versus 80%, P = .045). Three-year cumulative incidence of relapse (CIR) in the whole population was 20%; a higher incidence of relapse was associated with adverse cytogenetics (41% versus 16%, P = .018), ABCG2 overexpression (29% versus 15%, P = .04), and, marginally, age > 50 years (30% versus 14%, P = .06). We grouped patients according to the combination of these 3 risk factors: no patient relapsed within 3 years from SCT in the group without risk factors, whereas the 3-year CIR was 12% (95% confidence interval [CI], 2% to 25%) in the group with 1 risk factor and 47% (95% CI, 31% to 70%) in patients with 2 or 3 risk factors (P = .00005). In conclusion, allogeneic SCT does not seem to abrogate the negative prognosis associated with ABCG2 overexpression at diagnosis, specifically in terms of a higher relapse risk. ABCG2, age, and cytogenetics can predict AML relapse after SCT in patients who undergo transplantation while in CR.