[Impact of HER2, EGFR, IGF-1R, and VEGFR Expressions on the Outcome of Chemotherapy for Advanced Gastric Cancer]

We aimed to elucidate the clinical significance of the expressions of HER2, epidermal growth factor receptor (EGFR), insulin-like growth factor receptor (IGF-1R), and vascular endothelial growth factor receptor 1, 2, 3 (VEGF-R1, VEGF-R2, and VEGF-R3) in gastric cancer. The study group comprised 57 patients who had undergone gastrectomy at the National Cancer Center Hospital and subsequently received first-line chemotherapy (S-1 monotherapy [n=29] or irinotecan+cisplatin [n=28]) for recurrent or residual tumors. We performed immunohistochemical analysis of formalin-fixed paraffinembedded specimens of surgically removed primary tumors to determine the expressions of HER2, EGFR, IGF-1R, and VEGFR1 in tumor cells and the expressions of VEGF-R1, VEGF-R2, and VEGF-R3 in tumor stromal vessels. The expressions of HER2 (p=0.017) and IGF-1R (p=0.025) were significantly more common in intestinal type tumors than in diffuse type. The protein expressions did not correlate with tumor response in either chemotherapy-regimen group. Among the patients who underwent S-1 monotherapy, those with cytoplasmic VEGF-R1-positive tumors had significantly shorter progression-free survival (logrank, p=0.017). In the survival analysis of all the patients, coexpression of membranous IGF-1R and VEGF-R3 in stromal vessels was the most significant predictor of poor survival (hazard ratio, 1.82; 95% CI, 1.31-2.63; p<0.001). The results of our study will facilitate more efficient use of molecular targeted agents in patients with gastric cancer.