Invasive breast cancers classified as estrogen receptor negative and progesterone receptor positive (ER-/PR+) are relatively rare, accounting for up to 4% to 6% of breast cancer cases. In ER-/PR+ tumors, the cancer cells express progesterone receptors, but not estrogen receptors. Women with ER-/PR+ breast cancer are more likely to be premenopausal. Women with high breast density have an increased risk of breast cancer, including ER-/PR+ tumors. One 2012 study reported that percent mammographic density appears to be inversely associated with ER expression but might correlate positively with PR expression.

While similar to ER-/PR- disease, women with ER-/PR+ tumors have a somewhat better prognosis. Endocrine treatments such as tamoxifen that are effective for hormone receptor positive breast cancer are less successful in treating this type of cancer, although they are used.

Because ER-/PR+ tumors are rare, very few studies have specifically investigated this subtype. Please see our article on diet for ER-/PR+ cancer patients and survivors for available research pertaining to diet and supplements.

Below are links to recent studies on this topic. For a more complete list of studies, please click on ER-/PR+.