RAD21 and hepatocellular carcinoma: Several mechanisms have been suggested to underlie the radiosensitivity/radioresistance of HCC, including ferroptosis [57], CD133+CSCs [58], autophagy induction [10], suppression of DNA repair by melatonin-induced lncRNA RAD51-AS1 [59], miR320b/RAD21 axis [60], etc. However, the involvement of mitophagy in radioresistance in HCC has not been reported; thus, this report highlights mitophagy as an important therapeutic target for HCC radiotherapy.