It has been found that tumour cells tend to have reduced activities of those SODs compared to normal counterpart (Sykes et al, 1978; Oberley and Buettner, 1979; St Clair and Holland, 1991; Brorrello et al, 1993), and overexpression of SOD decreases malignant phenotypes in various cancers including breast cancer (Li et al, 1995), melanoma (Chruch et al, 1993) and glioma (Zhong et al, 1997). Here, SOD1 is linked to central nervous system cancer.