According to the present study, both in the liver and mammary gland, SOD concentrations were decreased in all the MNU-exposed individuals compared with the CTRL or PO-60 groups (G4 or G3), especially in the tumor-bearing individuals treated with PO-60 (G2 vs. G4 in the liver, G2 vs. G3 in the mammary gland; p < 0.0001), which may be related to the decline in antioxidant status brought on by mammary carcinogenesis. Here, SOD1 is linked to neoplasm.