Breast cancer is the mostcommon cancer type among women that globallycaused over 670 000 deaths in 2022. Basedon histological and molecular characteristics, breast tumors are dividedinto four major groups: luminal A, luminal B, human epidermal growthfactor receptor 2-positive (HER2+) and triple-negative breast cancer(TNBC)., HER2+ is an aggressive subtype of breastcancer and is associated with a worse prognosis for patients. The gene discussed is ERBB2; the disease is breast cancer.