progesterone receptor
Pronunciation: proh-JES-ter-ohn ree-SEP-ter
A protein found in breast cancer cells that can bind to the hormone progesterone and influence tumor growth and treatment response.
Full Definition
Progesterone receptor (PR) is a nuclear hormone receptor that binds to the hormone progesterone and regulates gene expression in breast cells. In breast cancer, PR status is determined by immunohistochemistry and reported as the percentage of cancer cells with nuclear staining. PR-positive tumors (typically ≥1% positive cells) often indicate a more favorable prognosis and better response to hormone therapy. PR status is usually evaluated alongside estrogen receptor (ER) status, and the combination provides important prognostic and predictive information for treatment planning.
Usage
Usage note: Use PR abbreviation only after first mention; report as percentage when describing test results.
In Context
- "The tumor was progesterone receptor positive with 70% nuclear staining intensity." — Pathology report
- "Loss of progesterone receptor expression may indicate endocrine resistance." — Research article