News organizations, and to some extent advocacy groups, speak of breast cancer as though it were a homogenous disease. That is a gross simplification.
In addition to differences based upon point of origin, such as ductal or lobular cancer, there are molecular differences which affect treatment options and cell aggressiveness. These four molecular types are luminal A, luminal B, HER2 positive and basal-like (triple negative). These molecular types may some day replace point-of-origin as our labels for breast cancer.