The SOD2 promoter is methylated in MM and correlates with decreased expression of SOD2. (A) The SOD2 promoter from −205 to +125, relative to the transcriptional start site, was screened by sodium bisulfite sequencing to determine methylated cytosines. The relative positions of the methylated cytosines are indicated by slash marks. Sequncing results from 10 clones are shown where • represents a methylated cytosine, whereas ○ represents an unmethylated cytosine. (B) The expression level of SOD2, as measured by DNA microarrays, is shown normalized to the expression of SOD2 in normal plasma cells. (C) Western blot showing expression of SOD2 in myeloma cell lines. Actin serves as the loading control. (D) Expression levels of SOD2 in cell lines treated with the demethylating agent zebularine. Actin serves as the loading control.