In breast cancer, particularly in the HER2-positive subtype, aberrant activation of the PI3K/AKT/mTOR and mitogen-activated protein kinase (MAPK/ERK) signaling pathways is frequently observed, promoting tumor cell proliferation, growth, migration, invasion, survival, and therapeutic resistance [55,56,57,58,59,60]. The gene discussed is ERBB2; the disease is breast carcinoma.