ERBB2 and invasive ductal breast carcinoma: ER: Estrogen receptor; PR: Progesterone receptor; HER2: Human epidermal growth factor receptor 2;​​​​​​​ NA: Not applicable; ​​​​​​​DCIS: Ductal carcinoma in situ; ​​​​​​​IDC: Invasive ductal carcinoma