KRAS mutations are not predictive for progression of preneoplastic gastriclesions

Individuals with atrophic gastritis (n = 863) were recruited to participate in a chemoprevention trial in Narino, Columbia, The volunteers were random ly assigned to intervention therapies, which included antibiotic treatment for Helicobacter pylori infection, and then daily dietary supplementation w ith antioxidant micronutrients in a 2(3) factorial design. Biopsies were ob tained according to a specified protocol from designated areas in the stoma ch for each individual at baseline (before intervention therapy), at year 3 , and at year 6, A systematic sample of 160 participants was selected from each of the eight treatment combinations, and the first exon of KRAS was ex amined for mutations, At year 3, the data indicated that individuals with K RAS mutations in their baseline premalignant stomach biopsies were 3.74 tim es as likely to progress to a higher premalignant stage than those who lack ed baseline mutations (P = 0.04; C, Gong et al,, Cancer Epidemiol, Biomark, Prev, 8:167-171, 1999), However, after 6 years, baseline KRAS mutations fa iled to predict histological progression. Also, KRAS mutation in 72-month b iopsies did not predict histological progression.