Which phenotype corresponds to absence of ER, PR, and HER2 expression?

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Multiple Choice

Which phenotype corresponds to absence of ER, PR, and HER2 expression?

Breast cancer subtypes are defined by receptor status for ER, PR, and HER2, which guides therapy choices. Absence of all three receptors—ER, PR, and HER2—defines the triple-negative phenotype. Without ER or PR, tumors won’t respond to endocrine therapies; without HER2, they won’t respond to HER2-targeted therapies. This makes triple-negative breast cancer the label for tumors that lack these receptors. In contrast, luminal A and luminal B cancers express estrogen receptor (and often progesterone receptor) and may have variable HER2 status, while HER2-enriched cancers overexpress HER2 and are typically ER/PR negative but HER2 positive, so they are not triple-negative.

Breast cancer subtypes are defined by receptor status for ER, PR, and HER2, which guides therapy choices. Absence of all three receptors—ER, PR, and HER2—defines the triple-negative phenotype. Without ER or PR, tumors won’t respond to endocrine therapies; without HER2, they won’t respond to HER2-targeted therapies. This makes triple-negative breast cancer the label for tumors that lack these receptors. In contrast, luminal A and luminal B cancers express estrogen receptor (and often progesterone receptor) and may have variable HER2 status, while HER2-enriched cancers overexpress HER2 and are typically ER/PR negative but HER2 positive, so they are not triple-negative.

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