Biomedical
Single Hormone Receptor–Positive Breast Cancer—Signal or Noise?
Peer Reviewed
Abstract
Canonical predictors for the prognosis of breast cancer include estrogen receptor (ER), progesterone receptor (PR), and ERBB2 (formerly HER2) receptor. In most cases, positive ER status is auspicious, but there are exceptions (young women, black women, and BRCA2 mutation carriers). The simplest designation, hormone receptor–positive cancers, includes tumors that express ER and/or PR (hormone receptor–negative cancers express neither). A complementary classification scheme groups patients into 4 categories based on gene expression profiles, 2 of which are hormone receptor positive (luminal A and luminal B). Luminal B tumors are less likely to express PR than luminal A tumors, they may be ERBB2 positive, they have a worse prognosis, and they are more likely to be treated with chemotherapy. Both luminal A cases and luminal B cases are candidates for tamoxifen or other hormone therapy.
Key Questions and Answers
1. What did Li and colleagues' study examine?
The study analyzed the relationship between estrogen receptor (ER) and progesterone receptor (PR) status in breast cancer survival, using data from the SEER database.
2. What is the controversy surrounding the ER-negative/PR-positive subtype?
The ER-negative/PR-positive subtype is debated, as it is biologically unusual and might be an artifact due to misclassification, though survival differences suggest it could be a legitimate category.
3. How might this affect treatment decisions?
If ER-negative/PR-positive is a valid subtype, alternative therapies like antiprogesterone treatment might be considered, as tamoxifen may not be effective for these patients.
