A bunch of cohorts (GSE12276, GSE6532‐GPL570, GSE1378, GSE1379, and GSE7390) of breast cancer demonstrated that higher ACE2 level was correlated to poor prognosis (relapse‐free survival [RFS] HR = 1.12, 95% CI = 1.02‐1.22, Cox P = .0156786; RFS/DMFS HR = 3.36, 95% CI = 1.21‐9.30, Cox P = .0198172; RFS HR = 1.38, 95% CI = 1.06‐1.79, Cox P = .0155929; RFS HR = 1.36, 95% CI = 1.08‐1.73, Cox P = .0100558; DMFS HR = 1.19, 95% CI = 1.04‐1.36, Cox P = .0137138; OS HR = 1.23, 95% CI = 1.08‐1.41, Cox P = .00252401) (Table S2 and Figure 3C‐L). Here, ACE2 is linked to breast cancer.