Premium Nahrungsergänzungsmittel | artgerecht

ESR1 – Estrogen Receptor 1: Function & Significance

ESR1 is a gene encoding the estrogen receptor alpha, playing a central role in hormonal signaling and in estrogen-dependent conditions such as breast cancer.

Regular tips about health Regular tips about health

Things worth knowing about "ESR1"

ESR1 is a gene encoding the estrogen receptor alpha, playing a central role in hormonal signaling and in estrogen-dependent conditions such as breast cancer.

What is ESR1?

ESR1 (Estrogen Receptor 1) is a human gene that encodes the estrogen receptor alpha (ERα), a ligand-activated transcription factor. When the female sex hormone estrogen binds to this receptor, it triggers the activation or repression of numerous target genes involved in cell growth, metabolism, reproduction, and tissue differentiation. ESR1 is central to female reproductive physiology and is closely associated with hormone receptor-positive breast cancer.

Biological Function

The estrogen receptor alpha encoded by ESR1 functions as a transcription factor. Upon estrogen binding, the receptor forms dimers, translocates to the cell nucleus, and binds to specific DNA sequences called Estrogen Response Elements (EREs), thereby regulating gene expression. Key biological roles include:

Regulation of the female reproductive cycle
Maintenance of bone density and bone remodeling
Modulation of cardiovascular function
Involvement in neurological and cognitive processes

Clinical Significance

Hormone Receptor-Positive Breast Cancer

ESR1 is the most clinically important gene in the context of breast cancer (mammary carcinoma). Approximately 70–80% of all breast cancers are classified as estrogen receptor-positive (ER+), meaning the tumor cells express estrogen receptor alpha and depend on estrogenic stimulation for growth. Determining the ESR1 status is therefore a standard component of pathological diagnosis in breast cancer.

ESR1 Mutations and Therapy Resistance

Acquired mutations in the ESR1 gene are of particular relevance in oncology. These mutations frequently arise in patients who have received prior aromatase inhibitor therapy and result in ligand-independent activation of the receptor, meaning the receptor remains constitutively active even without estrogen binding. Common mutation sites include D538G, Y537S, and Y537N within the ligand-binding domain of the receptor.

ESR1 mutations serve as a biomarker for acquired resistance to aromatase inhibitors
Detectable via liquid biopsy (circulating tumor DNA in the blood)
Therapeutic consequence: switching to agents such as fulvestrant or newer selective estrogen receptor degraders (SERDs) like elacestrant

Diagnosis and Testing

The ESR1 status can be assessed at multiple levels:

Immunohistochemistry (IHC): The standard method for assessing estrogen receptor expression in tumor tissue. Results are reported as the percentage of positive cells and staining intensity.
Liquid Biopsy: Detection of ESR1 mutations in circulating tumor DNA (ctDNA) from blood samples, particularly relevant in metastatic breast cancer.
Next Generation Sequencing (NGS): Comprehensive genomic profiling of tumor tissue to identify specific ESR1 mutations.

Therapeutic Relevance

Knowledge of the ESR1 status significantly influences the choice of endocrine therapy:

Tamoxifen: A selective estrogen receptor modulator (SERM) that blocks the estrogen receptor, used in ER+ breast cancer.
Aromatase inhibitors (e.g., letrozole, anastrozole): Suppress estrogen production and serve as first-line therapy in postmenopausal ER+ patients.
Fulvestrant: A selective estrogen receptor degrader (SERD) that promotes receptor degradation; may be effective in ESR1-mutated tumors.
Elacestrant: A novel oral SERD specifically approved for patients with ESR1 mutations following prior endocrine therapy.

ESR1 Beyond Oncology

Beyond cancer medicine, ESR1 holds significance in other medical fields. Genetic variants (polymorphisms) in the ESR1 gene have been associated with altered risk for the following conditions:

Osteoporosis and reduced bone mineral density
Cardiovascular disease
Endometriosis
Polycystic ovary syndrome (PCOS)
Alzheimer's disease (investigated in specific studies)

References

Jeselsohn R, Buchwalter G, De Angelis C, Brown M, Schiff R. ESR1 mutations as a mechanism for acquired endocrine resistance in breast cancer. Nature Reviews Clinical Oncology. 2015;12(10):573–583.
National Center for Biotechnology Information (NCBI). Gene: ESR1 – estrogen receptor 1. Bethesda (MD): National Library of Medicine (US). Available at: https://www.ncbi.nlm.nih.gov/gene/2099
Lumachi F, Santeufemia DA, Basso SM. Current medical treatment of estrogen receptor-positive breast cancer. World Journal of Biological Chemistry. 2015;6(3):231–239.

Building Blocks for a Healthy Life

As an integrated manufacturer, we develop & produce evidence-based, patented, and non-patented formulations. We work exclusively with plant and natural extracts according to the strictest purity & quality standards.
The combination of science & modern technology with the laws of nature creates solutions consistently tailored to humans – for the highest good: health.