Table 1.
Microarray classification of breast cancer
| Subtypes | ER, PgR, Her 2 Status | Other IHC features | Cell of origin | Other characteristics |
|---|---|---|---|---|
| Luminal A | ER + or PgR + or both, Her 2- | •Keratin 8/18 + ve | Luminal epithelial cell | •Younger age |
| •Best prognosis | ||||
| •Low rates of recurrence | ||||
| •Higher survival rate | ||||
| Luminal B | ER + or PgR + or both, Her 2+ | •Keratin 8/18 + ve | Luminal epithelial cell | •Higher tumor grade |
| •Poorer prognosis | ||||
| Basal like | ER-, PgR-, Her2-/+ | •Keratin 5/6/17 + ve | Basal/ myoepithelial cell/Bipotent progenitor | •15% |
| •EGFR + ve | •Younger age | |||
| •Associated with hereditary BRCA 1 | ||||
| •Poorer prognosis compared to other types | ||||
| •Spread to axillary nodes, less common to bones | ||||
| Her 2+ | ER-, PgR-, Her2+ | – | Late luminal progenitor | •20–25% |
| •Poorer grade | ||||
| •Lymph nodes positive | ||||
| •Early distant metastases | ||||
| •Poor prognosis | ||||
| •Frequent relapse | ||||
| Normal breast like | Tumors that do not fill into any of these categories | – | Luminal epithelial cell | •6–10% of all breast cancers |
| • Small tumors | ||||
| •Good prognosis | ||||
| •More common in postmenopausal | ||||
| •Associated with fibroadenomas | ||||
| Claudin low | ER-, PR-, Her2- | •Mesenchymal markers | Stem cell | •5–10% of all tumors |
| •Typically Triple negative | ||||
| •Low expression of cell-cell junction proteins (like E-Cadherin) | ||||
| •Lymphocytic infiltrates |
IHC Immunohistochemistry, ER Estrogen Receptor, PgR Progesterone Receptor, + Positive, - Negative