ER or Estrogen Negative (ER-)
“Breast cancer cells that are ER- do not need the hormone estrogen to grow”
https://www.oncolink.org/glossary/estrogen-receptor-negative
ER or Estrogen Positive (ER+)
“…high levels of estrogen in breast cancer cells help cancer grow and spread.”
https://my.clevelandclinic.org/health/diseases/er-positive-breast-cancer
PR or Progesterone Negative (PR-)
“Breast cancer cells that are PR- do not need the hormone progesterone to grow”
https://www.oncolink.org/glossary/progesterone-receptor-negative
PR or Progesterone Positive (PR+)
“…means it needs progesterone to grow.”
https://my.clevelandclinic.org/health/diseases/pr-positive-breast-cancer
HER2 Negative or Human Epidermal Growth Factor Receptor 2 (HER2-)
“Experts classify HER2-negative breast cancers based on what doesn’t fuel cancer growth — excess HER2. Instead, other factors cause tumors to form.”
https://my.clevelandclinic.org/health/diseases/her2-negative-breast-cancer
HER2 Positive or Human Epidermal Growth Factor Receptor 2 (HER2+)
“HER2-positive breast cancer is a breast cancer that tests positive for a protein called human epidermal growth factor receptor 2 (HER2). This protein promotes the growth of cancer cells.”
Triple Negative Breast Cancer (TNBC or – – -)
“Triple-negative breast cancer (TNBC) is an aggressive type of invasive breast cancer. TNBC differs from other types of invasive breast cancer in that it tends to grow and spread faster, has fewer treatment options, and tends to have a worse (outlook).”
https://www.cancer.org/cancer/types/breast-cancer/about/types-of-breast-cancer/triple-negative.html
Triple Positive Breast Cancer (TPBC or + + +)
“Triple-positive breast cancer is a type of breast cancer that occurs when breast cancer cells use estrogen receptors, progesterone receptors and the human epidermal growth factor 2 (HER2) protein to grow.”
Mammaries and Beyond 