Growth regulation by estrogen in breast cancer 1 (GREB1)

Growth regulation by estrogen in breast cancer 1 (GREB1) is an early estrogen-responsive gene encoding a protein that acts as a transcriptional coactivator and glycosyltransferase, regulating the function and stability of steroid hormone receptors such as estrogen receptor alpha (ERα) and progesterone receptor (PR)[2][3][6]. GREB1 expression is induced by estrogen and progesterone in hormone-sensitive tissues and cancers, where it is required for hormone-driven cell proliferation, gene regulation, and certain aspects of tumorigenesis—including in breast, ovarian, and prostate cancers as well as in endometriosis[1][2][3][5]. GREB1 stabilizes ERα by posttranslational O-GlcNAcylation and is essential for the transcriptional output of estrogen/progesterone signaling[2]. GREB1 is rarely directly targeted by current therapeutics but is under consideration as a therapeutic target and biomarker for hormone-dependent cancers[1][6].

Other names

Protein GREB1KIAA0575Gene regulated in breast cancer 1 proteinGene regulated by estrogen in breast cancerGrowth regulation by estrogen in breast cancer 1

Drugs affecting GREB1-linked pathways act upstream (e.g., estrogen receptor modulators like tamoxifen, aromatase inhibitors); GREB1 levels modulate hormone receptor function and downstream effects. GREB1 knockdown/inhibition blocks hormone-driven proliferation in cell lines and animal models.