SOD protects cells from oxidizing toxic products produced during aerobic respiration; this enzyme is involved in the conversion of superoxide radicals into oxygen and it has been shown that some defects in SOD activity are related to various cancers [34], although these data are often contradictory with each other; reduced SOD activity has been observed in brain tumor patients compared to normal subjects, while high SOD levels have been demonstrated to be associated with other cancers, such as breast and laryngeal carcinomas [35]. This evidence concerns the gene SOD1 and cancer.