Which receptor status trio is used to define common breast cancer subtypes in standard testing?

• A. ER, and HER2 status only
• B. ER, PR, and HER2 status
• C. Only ER status
• D. PR and HER2 status only

Answer: (B)

Receptor testing in breast cancer uses three markers: estrogen receptor, progesterone receptor, and HER2. This trio defines the common subtypes and guides therapy. If ER or PR is positive, endocrine (hormone) therapy is possible; if HER2 is positive, anti-HER2 therapies are used; when all three are negative, the tumor is typically treated as triple-negative with different chemotherapy approaches. The combinations ER/PR with or without HER2 give the major subtypes (HR+/HER2-, HR+/HER2+, HR-/HER2+, and HR-/HER2-), which is why including all three receptors is essential for standard classification. Choosing only one or two of these markers misses important treatment implications and subtype distinctions.