One of the first triggers contributing to IL-6 production and macrophage polarization in gastric carcinogenesis may be infection with H. pylori, as higher IL-6 mRNA levels are present in gastric mucosa (n=6 vs n= 6, P = 0.0891, Fig. 2B) as well as serum from H. pylori-infected healthy individuals (n=7 vs n= 4, P = 0.01, Fig. 2C) and cancer patients (n=24 vs n=24, P =0.3847 Supplementary Fig. S3) compared to uninfected controls. Here, IL6 is linked to infection.