Breast cancer comes in several types, mainly classified by the kind of cells affected:
- Carcinomas: Most common, starting in the gland cells of the milk ducts or lobules (e.g., ductal carcinoma in situ (DCIS) and invasive carcinoma).
- Angiosarcoma and sarcoma: Rare types starting in different cells in the breast.
Breast cancers are also classified based on proteins or genes they produce, like estrogen receptors, progesterone receptors, and the HER2 gene. These factors help determine the cancer stage and treatment options.