What you carry at this position in your DNA and what research says about it.
Breast Cancer Risk: 10/10 evidence, 13 publications.
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Sample genotype (not yours): A/A
Significantly Higher Breast Cancer Risk
Carrying two copies of the A allele is linked to a roughly 1.6-fold increase in breast cancer risk. This variant is one of the most well-studied genetic risk factors for hormone-receptor-positive breast cancer.
What this genotype means: Increased susceptibility to breast cancer; Higher likelihood of hormone-receptor-positive subtypes.
Sample genotype (not yours): A/G
Moderately Higher Breast Cancer Risk
Carrying one copy of the A allele is associated with a 1.2-fold increase in breast cancer risk. This common variant influences how the FGFR2 gene is expressed in breast tissue.
What this genotype means: Moderately increased susceptibility to breast cancer; Slightly higher likelihood of hormone-receptor-positive subtypes.
Sample genotype (not yours): G/G
Typical Breast Cancer Risk
Carrying two copies of the G allele represents the baseline genetic risk for breast cancer. This is the most common genotype globally and does not elevate risk.
What this genotype means: Baseline genetic risk for breast cancer; Standard levels of FGFR2 gene expression.
Gene function and biological role
Gene Function: The FGFR2 gene encodes fibroblast growth factor receptor 2, a protein that plays a critical role in cell growth, division, and survival [1]. During embryonic development, FGFR2 signaling is essential for bone growth and the formation of various tissues [2]. In adult tissues, altered signaling of this receptor can lead to uncontrolled cell proliferation, particularly in breast tissue [1]. Common variations in this gene are among the most strongly associated genetic risk factors for sporadic breast cancer [3].
Variant Impact: The rs2981579 variant is located in an intron, a non-coding region of the FGFR2 gene, and acts as a regulatory switch [1]. Rather than altering the structure of the receptor protein itself, this genetic change influences how much of the receptor is produced in breast tissue [1]. Specifically, the risk-associated A allele is linked to increased activity of the FGFR2 promoter, leading to higher levels of the receptor [1]. This overexpression of FGFR2 can promote cell division and increase susceptibility to hormone-receptor-positive breast cancer [4].
Key Insight: This variant does not change the structure of the FGFR2 protein, but instead acts as a volume dial, increasing the amount of the receptor produced in breast tissue.
Location: FGFR2. Chromosome 10 · 10q26.13 · 121.6 Mb
Estimated prevalence by population
Global 22.9%; European 16.7%; African 36.9%; East Asian 20.1%; South Asian 16.1%; Americas 18.8%; Ashkenazi 18.2%; Finnish 18.9%; Middle Eastern 22.0%; Amish 35.7%.
Estimated AA genotype frequency.
Global 48.3%; European 48.3%; African 47.7%; East Asian 49.5%; South Asian 48.0%; Americas 49.1%; Ashkenazi 48.9%; Finnish 49.1%; Middle Eastern 49.8%; Amish 48.1%.
Estimated AG genotype frequency.
Global 28.7%; European 34.9%; African 15.4%; East Asian 30.4%; South Asian 35.9%; Americas 32.1%; Ashkenazi 32.8%; Finnish 32.0%; Middle Eastern 28.2%; Amish 16.2%.
Estimated GG genotype frequency.
Showing effects for A/A genotype
Cancer & Oncology
Breast Cancer
Breast Cancer. Evidence: 10/10. Source: PMID 25751625. ~1.64x Risk.
ER-Positive Breast Cancer. Evidence: 3/10. Source: PMID 32366738. Increased Risk.
PR-Negative Breast Cancer. Evidence: 3/10. Source: PMID 28864454. Increased Risk.
Organ Systems
Dental & Oral Health
Jaw and Dental Alignment. Evidence: 6/10. Increased Risk.
Showing effects for A/G genotype
Breast Cancer. Evidence: 10/10. Source: PMID 25751625. ~1.20x Risk.
ER-Positive Breast Cancer. Evidence: 3/10. Source: PMID 32366738. Slightly Increased.
PR-Negative Breast Cancer. Evidence: 3/10. Source: PMID 28864454. Slightly Increased.
Jaw and Dental Alignment. Evidence: 6/10. Slightly Increased.
Showing effects for G/G genotype
Breast Cancer. Evidence: 10/10. Source: PMID 25751625. Typical Risk.
ER-Positive Breast Cancer. Evidence: 3/10. Source: PMID 32366738. Typical Risk.
PR-Negative Breast Cancer. Evidence: 3/10. Source: PMID 28864454. Typical Risk.
Jaw and Dental Alignment. Evidence: 6/10. Typical Risk.
What this genotype means for the people who carry it
Sample genotype: AA (Homozygous)
Double copies of the A allele are associated with the highest genetic risk of developing breast cancer at this locus [1]. Research indicates that this genotype increases the risk of breast cancer by approximately 1.64-fold compared to the common G/G genotype [2]. The increased risk is particularly pronounced for estrogen receptor-positive (ER+) breast cancers, which are sensitive to hormones [3]. Increased expression of the FGFR2 receptor in breast tissue is thought to drive this susceptibility by promoting cell growth [4]. While this genetic marker is a strong predictor of risk, it is not a direct cause of cancer and is considered a low-penetrance susceptibility variant [3]. Many people with this genotype never develop breast cancer, as lifestyle and other environmental factors play a major role. Knowing this status can help guide discussions with healthcare providers about personalized screening strategies.
Increased susceptibility to breast cancer; Higher likelihood of hormone-receptor-positive subtypes.
Sample genotype: AG (Heterozygous)
A single copy of the A allele is linked to a moderate increase in breast cancer susceptibility [1]. Studies show that this heterozygous genotype increases the risk of breast cancer by approximately 1.2-fold compared to the common G/G genotype [2]. The association is strongest for estrogen receptor-positive (ER+) breast cancers, which are the most common type [3]. Elevated expression of the FGFR2 gene in breast tissue is believed to underlie this increased susceptibility [4]. Because this is a low-penetrance genetic variant, it does not guarantee that cancer will develop [3]. Environmental factors, lifestyle choices, and other genetic markers heavily influence overall lifetime risk. Discussing these results with a healthcare provider can help put this moderate risk factor into perspective.
Moderately increased susceptibility to breast cancer; Slightly higher likelihood of hormone-receptor-positive subtypes.
Sample genotype: GG (Homozygous)
Two copies of the G allele represent the baseline genetic risk for breast cancer at this specific locus [1]. This genotype is the most common globally and is considered the standard reference or 'typical' profile [2]. Research has shown that individuals with this genotype do not have the elevated risk associated with the A allele [3]. The FGFR2 gene functions normally without the increased expression levels that can promote abnormal cell division [4]. While this genotype is protective compared to the risk alleles, it does not make someone immune to breast cancer. Standard screening guidelines and general health recommendations still apply. Maintaining a healthy lifestyle remains the most effective way to manage overall breast health.
Baseline genetic risk for breast cancer; Standard levels of FGFR2 gene expression.
Variants with shared genetic architecture
rs1219648 · FGFR2 Gene · Chr 10 · Breast Cancer Risk
rs2981582 · FGFR2 Gene · Chr 10 · Breast Cancer Risk
rs2981575 · FGFR2 Gene · Chr 10 · Breast Cancer and Prostate Risk
Low-penetrance susceptibility variants and postmenopausal oestrogen receptor positive breast cancer.
Large-scale genotyping identifies 41 new loci associated with breast cancer risk.
Content updated August 2026.
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