CDKN2A and breast cancer: Additional genetic mutations that have been utilized and used as tools to target breast cancer are cyclin-dependent kinase inhibitor 2A (CDKN2A), phosphatidylinositol 3-kinase Catalytic Subunit Alpha (PIK3CA), phosphate and tensin homolog (PTEN), and TP53, which is a tumor suppressor protein p53 that was previously mentioned [125,126,127,128].