estrogen receptor-positive (ER+) breast cancer

Estrogen receptor-positive (ER+) breast cancer is a type of breast cancer where the cancer cells have proteins called estrogen receptors on their surface. These receptors allow the cancer cells to use estrogen—a hormone common in women—to grow and multiply. Because of this, ER+ cancers often respond well to hormone-based treatments that block estrogen or its effects. This type accounts for about 70% of breast cancers and tends to grow more slowly than other types, making hormone therapy an effective and targeted approach to manage it.