Skip to main content
An official website of the United States government
Español
Government Funding Lapse
Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit cc.nih.gov.

Updates regarding government operating status and resumption of normal operations can be found at opm.gov.

luminal A breast cancer

(LOO-mih-nul … brest KAN-ser)
A subtype of hormone receptor-positive breast cancer. Luminal A breast cancer cells typically have estrogen receptor (ER) and progesterone receptor (PR) proteins inside them and a small amount or none of a protein called HER2 on their surface. Luminal A breast cancer cells also tend to have low levels of a protein called Ki-67, which is found only in cells that are dividing. Under a microscope, luminal A breast cancer cells look more like normal cells than other subtypes of breast cancer. They tend to grow slowly and have a good prognosis. Most breast cancers are luminal A.
Search NCI's Dictionary of Cancer Terms