Breast cancer cell receptors carry important prognostic information. The main receptors identified are estrogen receptors (ER), progesterone receptors (PR), and HER2/neu (HER2). Combinations of these receptors have been categorized by classes:
| Class | Characteristics |
| Luminal A | ER positive, PR positive, HER2 negative |
| Luminal B | ER or PR positive, HER2 negative |
| Luminal HER2 | ER or PR positive, HER positive |
| HER2 | ER and PR negative, HER2 positive |
| TNBC/Basalar | ER negative, PR negative, HER2 negative |