PR positive

Progesterone Receptor Positive (PR Positive) refers to a characteristic of some types of cancer, most notably breast cancer, where the cancer cells contain receptors for the hormone progesterone. These receptors are proteins found inside or on the surface of cells that bind to progesterone and can influence the behavior of the cells. When progesterone binds to these receptors, it can stimulate the cancer cells to grow. Testing for progesterone receptor status is an important part of diagnosing and planning treatment for breast cancer.

Overview

The presence of progesterone receptors is determined through a biopsy of the tumor, which is then analyzed in a laboratory. The test used to measure this is called an immunohistochemistry (IHC) assay, which provides a score indicating the proportion of cells that tested positive for the receptor. A score of at least 1% is generally considered PR positive.

Being PR positive is one of several factors that can influence the treatment and prognosis of breast cancer. Hormone therapy is a common treatment for hormone receptor-positive cancers, as it works by lowering the levels of hormones in the body or by blocking the hormones from supporting the growth of cancer cells.

Treatment

Treatment for PR positive breast cancer may include:

• Hormone therapy, such as tamoxifen or aromatase inhibitors, which block the effects of estrogen or lower estrogen levels in the body, respectively.
• Surgery, including lumpectomy or mastectomy, depending on the stage and size of the tumor.
• Chemotherapy, which may be used in addition to hormone therapy, especially in cases where the cancer is also HER2 positive or has other characteristics that make it more aggressive.
• Radiation therapy, often used after surgery to eliminate any remaining cancer cells in the breast or surrounding area.

Prognosis

The prognosis for PR positive breast cancer is generally favorable, especially when detected early and treated appropriately. Hormone receptor-positive cancers tend to grow more slowly than hormone receptor-negative cancers and are more responsive to hormone therapy.

Research and Future Directions

Ongoing research is focused on improving the understanding of how hormone receptor-positive cancers develop and respond to treatments. This includes studying the mechanisms of resistance to hormone therapy and developing new therapeutic strategies to overcome this challenge.

See Also

• Breast cancer
• Estrogen receptor positive
• HER2 positive
• Triple-negative breast cancer