APEX1 and neoplasm: The redox activity of Ref-1 regulates numerous transcription factors (TFs), including signal transducer and activator of transcription factor 3 (STAT3), activator protein 1 (AP-1), hypoxia-inducible factor (HIF-1α), nuclear factor κB (NF-κB), p53, and others, all known to be involved in cell growth, inflammation, and tumor metastasis (8).