64 Background: An altered expression of tumour angiogenesis-related factors has been constantly associated to a more aggressive phenotype and an increased relapse rate in several tumour types, including gastric cancer. Besides correlating with prognosis, tumour-driven angiogenesis seemed also able to influence response/resistance to chemotherapy in pre-clinical models. We examined the role of tumour angiogenesis genotyping in determining clinical outcome in metastatic gastric cancer patients receiving first-line chemotherapy. Methods: VEGF-A, VEGF-C, FLT1, KDR and FLT4 genotyping was performed on gastric tumours from 94 consecutive patients receiving platinum-based first-line chemotherapy. Results: Only theVEGF A rs25648 correlated with RR (PR = 18% among patients showing the VEGF A rs25648 CT or TT genotype vs. 44% among patients showing the VEGF A rs25648 CC genotype, p = 0.04). The VEGF A (rs2010963) and VEGF C (rs4604600 and rs7664413) correlated with mPFS and the VEGF A rs25648 and FLT4 rs307833 correlated with both mPFS and OS. Among other clinical variables tested (sex, age, ECOG performance status, gastrectomy, adjuvant chemotherapy, metastatic sites and second-line chemotherapy) only the use of second-line chemotherapy correlated with improved overall survival (10.2 months vs. 6.3 months for patients who received or did not receive second-line, p= 0.003). At multivariate the VEGF A rs25648 maintained an independent role in determining both median PFS (HR = 1.65 95% CI: 1.12-2.78, p= < 0.0001) and OS (HR = 1.58, 95% CI: 1.17-2.65, p = 0.0003). The use of second-line chemotherapy also showed an independent role in determining median OS (HR = 0.58, 95% CI: 0.38-0.87, p= 0.003). Conclusions: VEGF A rs25648 genotyping may help identifying a patients subgroup unlikely to benefit from a first-line, platinum-based combination and potentially candidate to alternative therapy choices. Our data may help designing future clinical trials with the aim to investigate the outcome of different chemotherapy regimens in different patients groups prospectively stratified according to angiogenesis profile.