In present study, we established different cohorts of immunodeficient mice models with patient-derived gastric cancer xenografts, and demonstrated that tumor growth were significantly suppressed in the cohort with sensitive-signature (low APTX and BRCA1, but high Topo1 mRNA expression level, Index = 0.95) when treated with irinotecan, but had no differences compared with cohort with resistant-signature (high APTX and BRCA1, but low Topo1 mRNA expression level, Index = 0.28). Here, BRCA1 is linked to gastric cancer.