Methylation-independent CHFR expression is a potential biomarker affecting prognosis in acute myeloid leukemia

CHFR acts as a tumor suppressor gene, which is frequently inactivated caused by its promoter hypermethylation in various solid tumors. Although a recent study showed that CHFR hypermethylation was a frequent event in acute myeloid leukemia (AML) and correlated with adverse clinical outcome, herein, we found that CHFR methylation was a rare event in patients with myeloid malignancies (including AML, chronic myeloid leukemia, and myelodysplastic syndromes), but its expression may serve as an independent prognostic biomarker in AML. CHFR expression was assessed by real-time quantitative PCR, whereas CHFR methylation was detected by methylation-specific PCR and bisulfite sequencing PCR. In AML patients, lower CHFR expression was associated with lower complete remission (CR) rate, and CHFR expression was significantly increased in CR after chemotherapy. Moreover, patients with lower CHFR expression showed shorter overall survival and leukemia-free survival, and multivariate analysis confirmed that lower CHFR expression was an independent risk factor in AML. Importantly, the prognostic value of CHFR expression was validated using the published Gene Expression Omnibus datasets. Notably, CHFR promoter was nearly unmethylated in patients with myeloid malignancies. Our findings revealed that lower CHFR expression was independently associated with unfavorable prognosis in AML. Moreover, aberrant CHFR promoter methylation was a rare event in myeloid malignances.