DDX43 promoter is frequently hypomethylated and may predict a favorable outcome in acute myeloid leukemia

Abstract

DEAD box polypeptide 43 (DDX43), a cancer/testis antigen (CTA), has been found to be overexpressed in various solid tumors and some hematologic malignancies. In the present work hypomethylation of the DDX43 gene was detected in 15% (32/214) of primary acute myeloid leukemia (AML) using real-time quantitative methylation-specific PCR (RQ-MSP). The level of DDX43 expression was correlated with DDX43 hypomethylation (R=0.277, P=0.014). Moreover, bisulfite sequencing confirmed the significant correlation between the methylation density and the level of DDX43 hypomethylation. Additionally, restoration of DDX43 expression in the K562 cell line by 5-aza-2'-deoxycytidine treatment confirmed a direct contribution of methylation in regulating the DDX43 gene. DDX43 hypomethylation was observed more frequently in favorable group (21.4%) and intermediate group (15.8%) than in poor group (0%) (P=0.009). AML patients with DDX43 hypomethylation had a better overall survival (median not obtained) than those with DDX43 methylation (median 8 months, 95% confidence interval 5.6-10.4 months) (P=0.014). In summary, the DDX43 gene is activated by promoter hypomethylation and DDX43 hypomethylation may be a favorable prognostic factor in AML.

Keywords: Acute myeloid leukemia; DDX43; Hypomethylation; Prognosis.