ACE2 and breast cancer: ACE2 only had a detrimental role in breast cancer (RFS: total number = 87, HR = 3.36, Cox P = 0.019817; distant metastasis-free survival: total number = 125, HR = 1.55, Cox P = 0.038243; OS: total number = 198, HR = 1.23, Cox P = 0.002524).