The long-term effect of Helicobacter pylori eradication on COX-1/2, 5-LOX and leukotriene receptors in patients with a risk gastritis phenotype--a link to gastric carcinogenesis.

To identify the role of eicosanoid-mediated pathways for gastric carcinogenesis, the expression of enzymes (COX-1, COX-2, 5-LOX) and receptors (BLT-1, CysLTR(1)) were immunohistochemically studied in H. pylori positive patients with a risk gastritis phenotype and either successful or unsuccessful eradication (n=12, each; followed up for a median of 5 years). Gastric cancer risk index improved significantly after successful eradication (p<0.001). Semiquantitative immunohistochemistry revealed distinct significant changes in the expression patterns for COX-2, CysLTR1, COX-1 and BLT-1 depending on the eradication outcome, whereas 5-LOX expression was not altered. These results suggest an involvement of the COX-LOX pathway in gastric carcinogenesis.