Ca: Cancer; IDC: Invasive ductal carcinoma; R: right; L: left, ILC: Invasive lobular carcinoma; DCIS: Ductal carcinoma in situ; ER: Estrogen receptor; PR: Progesterone receptor; HER2: Human epidermal growth factor receptor type 2; LN: Lymph nodes; (-): negative; (+): positive; VUS: Variant of unknown clinical significance; low: Low hormone receptor expression. This evidence concerns the gene ESR1 and invasive lobular breast carcinoma.