ESR1 and breast cancer: In terms of molecular typing, the types of breast cancer recognized are as follows: luminal A (ER+/PR+,HER-2-), Luminal B (ER+/PR+,HER-2+), HER-2 overexpression (ER-/PR-/HER-2+), and Basal-like (ER-/PR-/HER-2-).