APE1 is an essential endodeoxyribonuclease of the base excision repair pathway that maintains genome stability. It was identified as a pivotal factor favoring tumor progression and chemo-resistance through the control of gene expression by a redox-based mechanism. APE1 is overex-pressed and serum-secreted in different cancers, representing a prognostic and predictive factor, and a promising non-invasive biomarker. Strategies directly targeting APE1 funtions led to the identification of inhibitors showing a potential therapeutic value, which some of them are cur-rently in clinical trials. Interestingly, evidence indicates novel roles of APE1 in RNA metabolism still not fully understood, including its activity in processing damaged RNA in chemoresistant phenotypes, regulating oncomiRs maturation, and oxidized-RNA decay. Recent data point out a control role of APE1 in the expression and sorting of oncomiRs, within secreted extracellular vesicles (EVs). This review is focused on giving a portrait of the pros and cons of the last two decades of research aiming at the identification of inhibitors of the redox or the DNA-repair functions of APE1 for the definition of novel targeted therapies for cancer. We will discuss the new perspectives in cancer therapy coming from the unexpected finding of the APE1 role in miRNA processing for personalized therapy.