APEX1 and hepatocellular carcinoma: APEX1 protein is ubiquitous, but altered levels have been found in a variety of cancers, such as germ cell tumors, rhabdomyosarcomas, breast carcinomas, hepatocellular carcinomas (HCCs), non-small cell lung carcinomas, ovarian serous carcinomas, gastric carcinomas, esophageal squamous cell carcinomas, and bladder carcinomas [4,5].