APEX1 and head and neck cancer: Previous studies have reported increased expression of APE1 in bone marrow stromal cells of multiple myeloma [34], head and neck cancer, rhabdomyosarcomas, bladder, ovarian, gastro-esophageal and pancreatico-biliary cancers, prostate, thyroid and hepatocellular cancers and upregulated expression levels associated with poor prognosis in medulloblastoma [35].