Which breast cancer grouping corresponds to estrogen receptor positive and HER2 negative status?

• A. Luminal A
• B. Luminal B
• C. HER-2 Enriched
• D. Triple negative / TNBC

Answer: (A)

Breast cancers are classified by the receptors they express. When a tumor is estrogen receptor positive and HER2 negative, it fits the luminal A group. These tumors are usually also hormone receptor positive and tend to have lower proliferation (often a lower Ki-67 index), which explains their typically better prognosis. Because they rely on hormones for growth, endocrine therapies like tamoxifen or aromatase inhibitors are especially effective.

In contrast, luminal B cancers are ER-positive but either HER2 positive or have higher proliferation, making them more aggressive and sometimes requiring chemotherapy in addition to endocrine therapy. HER2-enriched cancers are usually ER and PR negative but HER2 positive, and triple-negative cancers lack ER, PR, and HER2. So the pattern described (ER positive, HER2 negative) maps best to luminal A.