In some cancers, such as colorectal, bladder, breast cancers, the anti-cancer mechanism of CTNNA1 is well understood, which has been translated into clinical practice, such as screening CTNNA1 to guide the management of HDGC; however, in other cancers, such as endometrial, ovarian, and pancreatic cancers, the mechanism and related signaling pathway of CTNNA1 remain to be fully understood. The gene discussed is CTNNA1; the disease is breast cancer.