Genetic polymorphism of IGF-I predicts recurrence in patients with gastric cancer who have undergone curative gastrectomy.

BACKGROUND: To our knowledge, no reports have evaluated the effects of genetic polymorphisms of insulin-like growth factor-I (IGF-I) on clinical outcomes of gastric cancer patients. METHODS: We retrospectively analyzed the impact of IGF-I polymorphisms on recurrence-free survival (RFS) in 430 patients with gastric cancer who underwent curative gastrectomy between 2001 and 2005 in our institution. RESULTS: Among the 430 gastric cancer patients, 345 were pathological stage I or II, while 85 were stage III or IV. The median 5-year RFS rate was 85.3% (95% confidence interval [CI] 81.4-88.5). In a multivariate Cox model (adjusted for age, gender, histology, pathological stage, adjuvant chemotherapy, and history of diabetes), two IGF-I polymorphisms, rs1520220 and rs2195239, were significantly associated with RFS (hazard ratio [HR] 0.60, 95% CI 0.40-0.91; and HR 0.60, 95% CI 0.41-0.89, respectively, in a per-allele model). When stratified by stage (I-II versus III-IV), rs1520220 in particular was associated with RFS in patients with stage III-IV disease, with a P-value for interaction of 0.01. CONCLUSIONS: Our findings indicate that genetic polymorphisms of IGF-I may have a substantial effect on recurrence for gastric cancer patients who have undergone curative gastrectomy. This information may help identify population subgroups that could benefit from IGF-I-targeting agents.