All in all, this study manifested that the IMRGs (DOHH, P4HA3 and MMP1) presented good efficiency for predicting GC prognosis, implying that this gene signature relevant to iron metabolism was a promising biomarker in foretelling the prognosis of GC, which would provide new idea on the digging of underlying predictive biomarkers for GC patients. The gene discussed is P4HA3; the disease is gastric cancer.