Question: what does estrogen and progesterone receptor negative mean?
Answer: ER+/PR-: About 13% of breast cancers are estrogen-receptor-positive and progesterone-receptor-negative. This means that estrogen, but not progesterone, may be supporting the growth and spread of the cancer cells. ER-/PR+: About 2% of breast cancers are estrogen-receptor-negative and progesterone-receptor-positive.