Table 3.
Histologic and molecular properties of specific type breast cancer
| Molecular subtype | Common histologic types | HG | ER status (by IHC) | HER2 status (by ISH/IHC) | Ki67 (by IHC) | Specific IHC/ molecular properties |
|---|---|---|---|---|---|---|
| Luminal A | Classical, lobular, tubular, cribriform | 1 or 2 | + | − | Low | Luminal CK +, E−cadherin +/− |
| Luminal B | Micropapillary | 2 or 3 | +/− | −/+ | High | Luminal CK +, p53 mutations |
| Basal like | Medullary, metaplastic, adenoid cystic, secretory | 3 | − | − | High | Basal CK+, p53 mDNA repair loss, EGFR+/− mutations |
| Mol. apocrine | Apocrine, plemorphic lobular | 2 or 3 | − | −/+ | High | Androgene receptor+ |
| Claudin-low | Metaplastic | 3 | − | − | High | Cancer like stem cell, EMT like, low E-cadherin level |
As depicted in the table, most specific type breast cancer are homogenous entities and are included in only one molecular subtype (such as adenoid cystic carcinoma basal like, micropapillary carcinoma luminal type). However, specific types such as classical and pleomorphic lobular carcinoma and apocrine carcinoma are heterogenous. The table depicts probable histologic grade, ER, HER2, Ki67 status for each molecular classification.