PTGS2 and neoplasm: The relationship between radiotherapy and ferroptosis is corroborated by several evidence, including the specific staining (e.g., C11-BODIPY) as well as the increased expression of specific markers (e.g., MDA, 4-HNE and prostaglandin-endoperoxide synthase 2, PTGS2) reflecting lipid peroxidation observed in IR-exposed cancer cell lines and tumor samples.