What you carry at this position in your DNA and what research says about it.
Cancer Progression Risk: 5/10 evidence, 24 publications.
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Sample genotype (not yours): G/G
Typical Cancer Progression Risk
Standard cancer progression rates and typical responses to adjuvant therapies are characteristic of this genetic profile. It is also linked to slightly higher waist circumference but lower liver enzyme levels.
What this genotype means: Typical baseline cancer prognosis; Standard response to cancer therapies; Slightly higher waist circumference.
Sample genotype (not yours): A/A
Elevated Cancer Progression Risk
An elevated risk of prostate cancer and reduced efficacy of certain breast cancer treatments are linked to this double-copy variant. It also correlates with higher liver enzymes and lower waist circumference.
What this genotype means: Elevated risk of cancer progression; Reduced efficacy of certain breast cancer therapies; Higher liver enzyme levels.
Sample genotype (not yours): G/A
Moderately Increased Cancer Progression Risk
A moderately increased risk of prostate cancer and faster tumor progression are associated with this single-copy variant. It may also influence liver enzyme levels and body fat distribution.
What this genotype means: Moderately higher risk of cancer progression; Slightly elevated liver enzymes; Slightly lower waist circumference.
Gene function and biological role
Gene Function: The FGFR4 gene encodes fibroblast growth factor receptor 4, a member of the receptor tyrosine kinase family that spans the cell membrane. This receptor plays a vital role in regulating cell proliferation, differentiation, and tissue repair by binding to specific growth factors. When activated, it triggers intracellular signaling cascades like the MAPK and PI3K pathways that promote cell survival and migration. However, abnormal activity or overexpression of this receptor is frequently observed in various epithelial cancers, where it can accelerate tumor growth and metastasis [1].
Variant Impact: A missense mutation at codon 388 of the FGFR4 gene alters the encoded amino acid from glycine to arginine (p.Gly388Arg). This specific change occurs within the transmembrane domain of the receptor, which anchors it to the cell membrane. The arginine substitution is thought to reduce the rate of receptor degradation, leading to prolonged signaling and increased cell motility [2]. Consequently, this variant has been extensively studied for its impact on cancer progression, treatment resistance, and metabolic traits.
Key Insight: The single amino acid change in this receptor alters its stability, making cancer cells more mobile and resistant to standard therapies.
Location: FGFR4. Chromosome 5 · 5q35.2 · 177.1 Mb
Estimated prevalence by population
Global 54.3%; European 48.3%; African 75.2%; East Asian 30.4%; South Asian 40.2%; Americas 44.9%; Ashkenazi 46.1%; Finnish 45.5%; Middle Eastern 60.1%; Amish 53.0%.
Estimated GG genotype frequency.
Global 37.7%; European 42.4%; African 23.0%; East Asian 49.5%; South Asian 46.4%; Americas 44.2%; Ashkenazi 43.6%; Finnish 43.9%; Middle Eastern 34.8%; Amish 39.6%.
Estimated GA genotype frequency.
Global 8.0%; European 9.3%; African 1.8%; East Asian 20.2%; South Asian 13.4%; Americas 10.9%; Ashkenazi 10.3%; Finnish 10.6%; Middle Eastern 5.0%; Amish 7.4%.
Estimated AA genotype frequency.
Showing effects for G/G genotype
Cancer & Oncology
Cancer Prognosis & Treatment Outcome
Cancer Progression. Evidence: 5/10. Source: PMID 16822847. Typical Risk.
Cardiovascular & Metabolic
Obesity & Body Composition
Waist Circumference. Evidence: 8/10. Source: PMID 34021172. Slightly Higher.
Blood Cell & Iron Traits
Hemoglobin Levels. Evidence: 8/10. Source: PMID 32327693. Typical.
Organ Systems
Liver Function & Disease
Liver Enzyme Levels. Evidence: 7/10. Source: PMID 40436827. Typical.
Showing effects for A/A genotype
Cancer Progression. Evidence: 5/10. Source: PMID 16822847. ~2x Higher Risk.
Waist Circumference. Evidence: 8/10. Source: PMID 34021172. Slightly Lower.
Hemoglobin Levels. Evidence: 8/10. Source: PMID 32327693. Higher.
Liver Enzyme Levels. Evidence: 7/10. Source: PMID 40436827. Higher.
Showing effects for G/A genotype
Cancer Progression. Evidence: 5/10. Source: PMID 16822847. Moderately Higher.
Waist Circumference. Evidence: 8/10. Source: PMID 34021172. Typical.
Hemoglobin Levels. Evidence: 8/10. Source: PMID 32327693. Slightly Higher.
Liver Enzyme Levels. Evidence: 7/10. Source: PMID 40436827. Slightly Higher.
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
The presence of two G alleles, which encode the reference glycine residue, represents the baseline state for cell receptor stability. Clinical studies indicate that this genotype is associated with a more favorable prognosis in breast and prostate cancers compared to carrying the variant arginine allele [1] [2]. In breast cancer patients, this typical form of the receptor allows standard adjuvant therapies like Herceptin to work with expected efficacy [1]. Furthermore, meta-analyses confirm that individuals with this baseline genotype do not experience the accelerated tumor progression or increased metastatic risk seen with the variant [3]. On the metabolic side, large-scale genetic studies associate this genotype with a slight increase in waist circumference and waist-to-hip ratio [4] [5]. Conversely, it is linked to lower baseline levels of the liver enzyme alanine aminotransferase [6].
Typical baseline cancer prognosis; Standard response to cancer therapies; Slightly higher waist circumference.
Sample genotype: AA (Homozygous)
The homozygous A/A state results in all FGFR4 receptors having the arginine residue in their transmembrane domain. This homozygous state is linked to a 2-fold increase in prostate cancer risk and a higher likelihood of tumor metastasis [1]. In breast cancer patients, this genotype is associated with resistance to adjuvant therapies, making treatments like Herceptin less effective [2]. The prolonged signaling of the arginine-containing receptor enhances cancer cell motility and aggressiveness [3]. Beyond oncology, this genotype is associated with higher baseline levels of the liver enzyme alanine aminotransferase [4]. It also correlates with elevated hemoglobin levels, indicating potential effects on red blood cell production [5]. Interestingly, it is associated with a slightly lower waist circumference and waist-to-hip ratio [6].
Elevated risk of cancer progression; Reduced efficacy of certain breast cancer therapies; Higher liver enzyme levels.
Sample genotype: GA (Heterozygous)
A single copy of the A allele, which encodes the arginine variant, alters the transmembrane domain of the FGFR4 receptor. This structural change is associated with a 1.2-fold increased risk of developing prostate cancer and can accelerate tumor progression [1] [2]. The modified receptor is more stable and degrades slowly, which keeps growth signaling active longer and promotes cell migration. Large meta-analyses have confirmed that carrying this variant is linked to worse prognosis across several cancer types, including breast and colon cancers [3]. In addition to oncological risks, genome-wide association studies link this genotype to slightly elevated levels of the liver enzyme alanine aminotransferase [4]. However, it is also associated with a slightly lower waist circumference and waist-hip ratio compared to the G/G genotype [5] [6].
Moderately higher risk of cancer progression; Slightly elevated liver enzymes; Slightly lower waist circumference.
Variants with shared genetic architecture
rs1966265 · FGFR4 Gene · Chr 5 · Body Shape and Metabolism
rs6556301 · FGFR4 Gene · Chr 5 · Body Fat Distribution
rs2011077 · FGFR4 Gene · Chr 5 · Prostate Health Risk
Meta and pooled analyses of FGFR4 Gly388Arg polymorphism as a cancer prognostic factor.
FGFR4 Arg388 allele is associated with resistance to adjuvant therapy in primary breast cancer.
Predicted loss and gain of function mutations in ACO1 are associated with erythropoiesis.
Content updated August 2026.
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