Hematoxylin and eosin (H&E) staining

H&E staining of paraffin-embedded normal gastric tissues and cancer tissues in patients with RGA were performed by a pathologist using an established methodology. The steps of H&E staining are briefly described as follows: i) Sections of tissue samples were dewaxed with xylene and washed with various concentrations of ethanol (100, 100, 95 and 80%); ii) stained with 0.5% hematoxylin for 5 min, washed with water for 10 min and then distilled water for 5 sec; iii) soaked in hydrochloric acid ethanol for 30 sec and then water for 15 min; iv) 0.5% eosinstaining for 2 min; v) conventional dehydration, transparency and neutral resins mount; vi) the results were observed using light microscopy (magnification, ×200). All steps were performed at room temperature (25°C).