rs11249433: Understanding the 1p11.2 Breast Cancer Susceptibility Locus
The genetic variant rs11249433 is a single nucleotide polymorphism located in an intergenic region on chromosome 1p11.2. It is recognized in scientific literature for its association with an increased risk of developing breast cancer, specifically showing a stronger correlation with estrogen receptor-positive (ER-positive) and lobular breast cancer subtypes.
What each genotype means
Baseline breast cancer risk
This genotype is considered the non-risk variant in populations of European descent. Research indicates that carriers of this genotype do not show the increased association with estrogen receptor-positive (ER+) or lobular breast cancer observed with the G allele.
This is the most common genotype in populations of European ancestry.
Slightly increased breast cancer risk
Carrying one copy of the G allele is associated with a statistically significant, modest increase in the risk of developing breast cancer, particularly ER-positive and lobular subtypes. Studies suggest this variant may influence the expression of the nearby NOTCH2 gene, though the clinical significance of this expression change is not fully understood.
This genotype is common in populations of European ancestry but is significantly rarer in East Asian and African populations.
Increased breast cancer risk
Carrying two copies of the G allele is associated with a higher statistical risk for breast cancer compared to the AA genotype, specifically for ER-positive and lobular histology tumors. This association has been consistently observed in European populations, though it has not been detected in East Asian or African cohorts.
This genotype is found in a significant portion of individuals of European ancestry, while being very uncommon in East Asian and African populations.
What is rs11249433?
The variant rs11249433 is a single nucleotide polymorphism (SNP) situated at the 1p11.2 locus on chromosome 1. In genetics, a SNP represents a variation at a single position in the DNA sequence among individuals. This specific variant is located in an intergenic region, meaning it does not sit within the protein-coding sequence of a known gene. However, its location is significant because it resides in a region that may influence the regulation of nearby genes. Research has identified this variant through genome-wide association studies (GWAS), which scan the entire genome to find markers that appear more frequently in individuals with a specific condition compared to those without it. Because it is a common variant, it has been extensively studied to understand its role in complex health predispositions, particularly in the context of breast cancer susceptibility in populations of European descent.
Association with Breast Cancer Subtypes
Scientific research has consistently linked rs11249433 to breast cancer risk, but the association is nuanced. Meta-analyses involving tens of thousands of cases and controls have shown that the variant is primarily associated with estrogen receptor-positive (ER-positive) breast tumors. Furthermore, studies have highlighted that this variant shows a stronger association with invasive lobular breast cancer compared to invasive ductal breast cancer. Some research suggests that this variant may influence the expression of the nearby NOTCH2 gene, particularly in ER-positive tumor tissues, which may contribute to the observed biological differences. It is important to note that while these statistical associations are significant, they describe population-level trends rather than individual outcomes. The evidence for this association is considered moderate, as it is robust in European populations but has not been consistently replicated in East Asian or African populations, indicating that the genetic architecture of breast cancer risk can vary significantly by ancestry.
Population Frequency and Ancestry
The frequency of the rs11249433 variant varies across different global populations. Published meta-analyses have noted that the association between this SNP and breast cancer risk is most evident in women of European ancestry. In contrast, studies conducted among East Asian and African populations have generally not detected significant associations with breast cancer susceptibility for this specific variant. This discrepancy highlights the importance of considering genetic background when interpreting health-related genetic data. Because the variant is common in European populations, many individuals may carry one or two copies of the risk allele. However, carrying the variant does not mean an individual will develop breast cancer, as the condition is multifactorial, involving a complex interplay of genetics, environment, and lifestyle factors. Researchers continue to study these population-specific differences to better understand the underlying biology of cancer susceptibility.
Interpreting Genetic Information
Understanding your genetic profile regarding rs11249433 should be approached with a focus on education rather than clinical diagnosis. This variant is one of many genetic factors that contribute to breast cancer risk, and it is not a standalone predictor of health. If you have concerns about your personal or family history of breast cancer, the most appropriate step is to consult with a healthcare professional or a genetic counselor. They can provide a comprehensive risk assessment that considers your entire medical history, lifestyle, and family background, which are often more informative than a single genetic marker. Genetic information is a tool for understanding biological predispositions, but it cannot replace clinical screening or professional medical advice. Always discuss any findings from genetic testing with a qualified clinician who can help you interpret the results in the context of your overall health and guide you toward appropriate preventative screenings or lifestyle considerations.
How common is this variant?
The rs11249433 variant is common in populations of European descent, where it has been extensively studied. Research indicates that significant associations with breast cancer risk are primarily observed in these populations, while studies in East Asian and African populations have not consistently found similar links.
Frequently asked questions
Does having the rs11249433 variant mean I will get breast cancer?
No, having this variant does not mean you will develop breast cancer. It is a common genetic marker associated with a modest change in statistical risk, and most people who carry the variant will never develop the disease.
Is rs11249433 a diagnostic test for breast cancer?
No, rs11249433 is not a diagnostic test. Breast cancer is a complex disease influenced by many genes, environmental factors, and lifestyle choices, and this single SNP provides only a small piece of information.
Should I change my screening schedule based on this variant?
You should not change your medical screening schedule based on this variant alone. Always discuss your genetic results and your personal risk factors with your doctor to determine the appropriate screening plan for you.
Why is the association with rs11249433 different across ancestries?
Genetic associations can vary by ancestry due to differences in the overall genetic architecture of populations, including how different variants are linked together on the same chromosome. This is why findings in one population may not be replicated in another.
Sources & further reading
Educational information only, last refreshed 10/27/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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