MMP9 and neoplasm: An important fingerprint of hypoxia (69) was registered in HCT116 cells at 24 h after the addition of 20 MBq/mL [64Cu]CuCl2, characterized by the overexpression of the HMOX1 (70) and MMP9 (71) genes that can elicit hypoxic radioresistance (72) in the tumor niche (73).