The COX7A1 gene was obtained by further molecular screening using immune response ssGSEA score, and the predictive effect of COX7A1 on the prognosis of GC patients was verified in several data sets: GC patients with high expression of COX7A1 in GC tissues had poor prognosis; the COX7A1 expression in the tumor tissues was significantly lower than that in the paracancerous/normal tissues; and the COX7A1 expressions were higher in patients with older age and deeper invasion. Here, COX7A1 is linked to gastric cancer.