SOD2 and colorectal carcinoma: Our immunohistochemical (IHC) staining data demonstrated that relative to its expression in the normal colorectal tissue samples, the expression of SOD2 in the CRC tissues was significantly increased as the disease progressed from stage I to stage IV (stage II: 2.2-fold, p < 0.05; stage III: 3.1-fold, p < 0.01; stage IV: 4.4-fold, p < 0.001); similarly, an estimated 2.4-fold increase was observed in SOD2 expression in the metastatic disease group, compared to the normal group (p < 0.05) (Figure 3A,B).