ENHANCED EXPRESSION OF MANGANESE SUPEROXIDE-DISMUTASE MESSENGER-RNA AND INCREASED TNF-ALPHA MESSENGER-RNA EXPRESSION BY GASTRIC-MUCOSA IN GASTRIC-CANCER

Manganese superoxide dismutase (Mn-SOD), a mitochondrial enzyme, is a cytokine-regulated acute-phase protein that protects cells from free r adicals. The current investigations examined the in vivo regulation of the expression of Mn-SOD mRNA and tumor necrosis factor alpha (TNF al pha) mRNA in gastric carcinoma tissue. The expression of these transcr ipts in breast carcinoma tissue also was examined because breast cance r is a much more TNF-sensitive tumor than gastric cancer. TNF alpha mR NA was markedly increased in gastric carcinoma tissue (p < 0.005). The re were significantly higher levels of Mn-SOD mRNA in gastric carcinom a tissue than in noncancerous tissue (p < 0.0001). The level of Mn-SOD mRNA in gastric carcinoma tissue was higher than that in breast carci noma tissue (p < 0.005). Up-regulation of Mn-SOD mRNA in gastric carci noma tissue most likely serves as a protective mechanism against super oxide radicals and TNF cytotoxicity.