Moreover, by cross‐validation with GEO data sets, we identified nine tumour microenvironment‐related genes to be significantly associated with poor prognosis of GC patients, which were ITGA5, LAMA2, LAMB1, THBS1, TNN, ITGA9, ITGB1, ITGB5 and LAMC1. This evidence concerns the gene ITGA5 and gastric cancer.