APEX1 and cancer: Dysregulation of APE1 has been demonstrated to be associated with a couple of diseases such as cancer,4 neurodegenerative diseases5 and cardiovascular disorders.6 Abnormal expression and subcellular distribution of APE1 have been linked to tumor metastasis.7 From a therapeutic perspective, APE1 has drawn significant attention as an emerging target for some cancer types.4 This motivates fabricating molecular tools to probe and regulate the cellular APE1 activity.