ESR1 rs2046210: What Your Genotype Means
The rs2046210 variant is a common genetic change located near the ESR1 gene, which encodes the estrogen receptor alpha. Research has identified this variant as a susceptibility locus statistically associated with varying levels of breast cancer risk across different populations.
What each genotype means
Baseline risk profile
This genotype is considered the baseline or reference state for this variant. Research indicates that individuals with this genotype do not carry the specific allele associated with the increased breast cancer risk observed in some populations.
This is a common genotype found across many global populations.
Slightly increased risk
This genotype is associated with a statistically higher risk of breast cancer in certain studies compared to the baseline C/C genotype. Because this association can vary significantly by ancestry and environmental factors, it should be viewed as one small piece of a much larger health picture.
This is a common genotype, frequently observed in both European and Asian populations.
Increased risk profile
Individuals with this genotype have been observed in some studies to have a higher statistical association with breast cancer risk compared to those with the C/C genotype. This association is not a diagnosis, and the level of risk may differ based on your specific ancestry and other genetic or lifestyle factors.
This genotype is present in a significant portion of the population, though its frequency varies by ethnic background.
Understanding the Variant and Its Location
The rs2046210 variant is a single nucleotide polymorphism (SNP) situated approximately 180 kilobases upstream of the ESR1 gene on chromosome 6. In genetics, a SNP represents a variation at a single position in the DNA sequence among individuals. Because this variant is located in a non-coding regulatory region, it is thought to influence how the nearby ESR1 gene is expressed rather than changing the structure of the protein itself. Scientists study these non-coding variants to understand how they act as 'switches' that turn genes on or off in specific tissues, such as breast tissue. By mapping these locations, researchers can better understand the complex regulatory networks that govern cellular behavior and how disruptions in these networks might contribute to disease susceptibility.
The Role of the ESR1 Gene
The ESR1 gene provides instructions for making the estrogen receptor alpha (ERα) protein. This protein is a nuclear hormone receptor that functions as a ligand-activated transcription factor, meaning it binds to estrogen and then travels to the cell's nucleus to regulate the activity of various other genes. Estrogen signaling is critical for the development and function of many tissues, including the breast, uterus, and ovaries. Because estrogen promotes cell growth, the regulation of ERα is a central focus in breast cancer research. When the expression of ESR1 is altered, it can affect how breast cells respond to hormonal signals, potentially influencing cell proliferation and survival. Understanding the genetic factors that modulate ESR1 expression is therefore essential for characterizing the biological pathways involved in breast health.
Research Associations and Evidence Strength
The association between rs2046210 and breast cancer has been investigated in numerous genome-wide association studies (GWAS). Evidence suggests a moderate association, with the variant identified as a susceptibility locus in both Asian and European populations. Some studies have specifically linked this SNP to an increased risk of triple-negative breast cancer, while others have explored its role in ER-positive disease. It is important to note that the strength of these associations can vary significantly depending on the ancestry of the study participants and the specific subtype of breast cancer being analyzed. While some research indicates that the risk allele may influence ERα protein levels in breast tissue, the findings are not uniform across all studies. Consequently, the evidence is considered moderate, reflecting the complex, polygenic nature of breast cancer risk where many small-effect variants interact with environmental factors.
Population Frequency
The rs2046210 variant is considered a common SNP, meaning it is found at relatively high frequencies across diverse global populations. Because it is common, most individuals carry at least one copy of the variant, and it is not considered a rare mutation. Allele frequencies can differ between ancestral groups, which is a standard observation in human genetics. Researchers often use these frequency differences to help fine-map the variant and determine if the association with disease risk is consistent or if it is modified by other genetic or environmental factors unique to specific populations. Large-scale databases like gnomAD provide granular data on these frequencies, helping scientists refine their understanding of how common variants contribute to the overall genetic architecture of complex diseases like breast cancer.
Interpreting Your Genetic Information
Genetic information regarding variants like rs2046210 provides insight into statistical predispositions rather than definitive medical outcomes. A statistical association with breast cancer risk does not mean that an individual will develop the disease, nor does the absence of a risk allele guarantee protection. Breast cancer is a multifactorial condition influenced by a combination of genetics, lifestyle, and environmental exposures. If you have questions about your personal risk profile or family history, it is essential to consult with a healthcare professional or a certified genetic counselor. They can provide context based on your full medical history and help you understand what screening or preventative measures might be appropriate for you. Never use genetic data to make independent medical decisions or to alter any prescribed treatments without professional guidance.
How common is this variant?
The rs2046210 variant is a common polymorphism found across various global ancestries, with allele frequencies varying by population group.
Frequently asked questions
Does having the rs2046210 risk allele mean I will get breast cancer?
No. This variant is only one of many factors that contribute to breast cancer risk. Most people who carry the risk allele will never develop the disease, as it is a complex condition influenced by many genetic and environmental factors.
How can I find out my genotype for rs2046210?
Your genotype for this variant may be included in reports from direct-to-consumer genetic testing services. If you have your raw data, you can search for the rsID, but you should discuss any findings with a healthcare provider.
Is rs2046210 the same as a BRCA1 or BRCA2 mutation?
No. rs2046210 is a common variant associated with a modest change in risk, whereas BRCA1 and BRCA2 mutations are rare, high-penetrance variants that significantly increase the risk of breast and ovarian cancer.
Should I change my breast cancer screening schedule based on this SNP?
You should not change your screening schedule based on a single SNP. Breast cancer screening guidelines are based on your overall risk profile, including family history and age, which should be discussed with your doctor.
Sources & further reading
Educational information only, last refreshed 10/1/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Common polymorphism in estrogen receptor alpha (ESR1) affecting target tissue responsiveness to estrogen, recurrent pregnancy loss risk, and bone-reproductive axis interactions.
This SNP is located in the estrogen receptor alpha gene, which plays a critical role in modulating physiological responses to stress and hormonal regulation.
Estrogen receptor 1 regulatory variant associated with variation in timing of menarche and bone density response to sex hormones.
Regulatory variant in ESR1 linked to endometrial receptivity and altered response to ovarian stimulation.
Intronic variant in estrogen receptor 1 (ESR1) associated with age at menarche and natural menopause onset in genome-wide studies.
Estrogen receptor 1 variant associated with altered circulating estradiol levels, ovulatory response, and timing of natural menopause.