In opposition, the protein and mRNA levels of IL-8 were significantly higher in patients with family histories of gastric cancer and without H. pylori infection than those without both H. pylori infection and family histories of gastric cancer (P<0.05; Figs 2 and 3), and they were also significantly higher in patients with family histories of gastric cancer than those without family histories of gastric cancer (P<0.05; Figs 2 and 3). The gene discussed is CXCL8; the disease is gastric cancer.