rs28419191: What Your Genotype Means
rs28419191 is an intergenic single-nucleotide polymorphism located on chromosome 5q31. Multi-ancestral genome-wide association studies have identified statistical links between this variant and oral cavity cancer susceptibility, as well as radiotherapy-induced mucositis. Because the evidence linking this non-coding locus to disease outcomes is currently limited and functionally complex, it serves as a statistical marker rather than a direct clinical diagnostic.
What each genotype means
Increased risk profile
Research indicates that the C allele of this variant is associated with an increased risk of oral cavity cancer and, in some studies, a higher susceptibility to radiation-induced mucositis during head and neck cancer treatment. Because this is a complex genetic association, this result should not be used for medical diagnosis or clinical decision-making.
The C allele is the major allele at this position, making the C/C genotype the most common configuration across most global populations.
Intermediate risk profile
Carrying one copy of the T allele alongside the C allele may result in a different risk profile compared to those with two copies of the C allele. Current evidence suggests this variant is linked to oral cavity cancer risk, but the functional impact remains unclear and requires further study.
This heterozygous genotype is found at varying frequencies depending on ancestral background, reflecting the distribution of the minor T allele.
Lower risk profile
Individuals with this genotype carry two copies of the T allele, which is less frequently associated with the increased cancer risks observed in carriers of the C allele. As this is an intergenic regulatory variant, its specific biological mechanism is not fully understood, and it should not be interpreted as a definitive health outcome.
The T/T genotype is the least common of the three, occurring at a frequency determined by the prevalence of the minor T allele in specific ancestral populations.
Genomic Location and Variant Biology
The single-nucleotide polymorphism rs28419191 is positioned in an intergenic region on chromosome 5 (band 5q31). Because it resides outside the protein-coding exons of human genes, it does not alter an amino acid sequence directly. Instead, research indicates that this non-coding region functions primarily as a regulatory locus. Genetic studies show that rs28419191 is in strong linkage disequilibrium with rs1131769, a missense variant within the STING1 gene, and sits approximately 4 kilobases upstream of the ECSCR gene. Functional colocalization models demonstrate that rs28419191 correlates significantly with expression levels of CTNNA1 (catenin alpha 1) in whole blood, a gene vital for intercellular adhesion and actin cytoskeleton organization. While its exact molecular mechanism remains under exploration, its position suggests that it may influence regional chromatin architecture or transcriptional efficiency.
Research Associations with Cancer Susceptibility
In a comprehensive multi-ancestral genome-wide association study (GWAS) evaluating more than 19,000 head and neck squamous cell carcinoma cases and 38,000 controls, rs28419191 emerged as a notable risk variant specifically for oral cavity cancers (odds ratio approximately 1.23). The statistical signal appeared to be largely driven by non-HPV-related tumors rather than HPV-positive oropharyngeal cancers. The high linkage disequilibrium with STING1 variants suggests an involvement in innate immune surveillance or cellular stress responses, although researchers observed no direct correlation with STING1 transcript levels in whole blood. Because oral cavity cancers arise from complex multi-factorial interactions between genetics and environmental carcinogens such as tobacco and alcohol, the statistical effect size of rs28419191 confers only a modest shift in relative odds across populations.
Links to Radiotherapy Toxicity and Mucositis
Beyond cancer susceptibility, radiogenomics research has highlighted rs28419191 in the context of treatment-related side effects. A multi-stage association study of head and neck cancer patients receiving definitive radiotherapy identified the rs28419191 locus as genome-wide significant for acute, moderate-to-severe radiation-induced oral mucositis. In European patient discovery and replication cohorts, the C allele was associated with higher odds of painful mucosal inflammation following radiation therapy. However, replication attempts in an independent Asian cohort yielded inconclusive findings, potentially influenced by differing underlying allele frequencies, sample sizes, or baseline treatment variations. Consequently, while rs28419191 is a promising candidate for understanding individual mucosal sensitivity to ionizing radiation, evidence regarding its universal impact across different treatment protocols remains limited.
Population Frequency and Ancestral Distribution
Allele frequencies for rs28419191 exhibit measurable variation across world populations in reference databases such as 1000 Genomes and gnomAD. In European cohorts evaluated in both cancer mapping and radiogenomic investigations, the C allele represents the major allele with an estimated frequency near 87%. Conversely, its frequency fluctuates significantly across other ancestral groups, such as East Asian populations where the correlated C allele frequency drops to roughly 77%, and distinct patterns appear in African and Admixed American ancestries. These divergent baseline frequencies underscore why multi-ancestral cohorts are crucial for discovering and validating genetic risk loci. Because linkage disequilibrium architecture varies widely around 5q31 between ancestral populations, the precise risk-tagging capacity of rs28419191 must be interpreted within a patient's specific genomic background.
Clinical Interpretation: What You Can and Cannot Do
It is critical to recognize that rs28419191 is an exploratory statistical marker, not a diagnostic test. Carrying one or two copies of a risk-associated allele does not mean you will develop oral cavity cancer or experience severe radiation side effects, nor does a protective or reference genotype grant immunity. Cancers of the head and neck are predominantly driven by established environmental exposures, including tobacco smoke, heavy alcohol consumption, and viral infections. Modifiable lifestyle factors remain the single most effective way to lower head and neck cancer risk. Furthermore, while radiogenomic studies point to biological pathways of tissue vulnerability, genetic profiling of this variant is not approved for altering radiation therapy dosing or schedules. Any clinical questions regarding cancer screenings or radiation oncologic treatments should always be reviewed directly with an oncologist or medical provider.
How common is this variant?
Allele frequency varies significantly across ancestral groups in 1000 Genomes and gnomAD; the C allele is common in European cohorts (around 87%) but shows lower and variable prevalence across East Asian, African, and other ancestral populations.
Frequently asked questions
What does having the rs28419191 variant mean for my health?
Carrying an associated allele at rs28419191 indicates a minor statistical shift in relative risk for oral cavity cancer and radiotherapy-induced mucositis in population-level studies. It is not a genetic diagnosis and does not guarantee that you will develop cancer or experience radiation side effects. Modifiable factors like tobacco and alcohol use play far more substantial roles in head and neck cancer risk.
Does rs28419191 belong to a specific protein-coding gene?
No, rs28419191 is an intergenic variant situated on chromosome 5q31, outside of protein-coding exons. However, it is located near the ECSCR and STING1 genes and demonstrates strong statistical colocalization with the expression of the CTNNA1 gene in blood tissue. Researchers study it as a putative regulatory element rather than a direct protein-altering mutation.
Can testing for rs28419191 change my cancer radiation therapy plan?
No, testing for rs28419191 is not currently used in standard clinical oncology to alter radiation doses or schedules. While research indicates an association with higher rates of oral mucositis, the evidence is limited and exploratory. Any decisions regarding radiation therapy and supportive care for side effects must be made in consultation with your radiation oncologist.
Is the effect of rs28419191 the same across all ethnic backgrounds?
The frequency and statistical impact of rs28419191 differ across ancestral groups. While associations with oral cavity cancer were observed in multi-ancestral meta-analyses, some radiogenomic findings failed to replicate in Asian populations where allele frequencies and genetic backgrounds diverge. Continued multi-ancestral research is required to clarify how this variant functions across different groups.
Sources & further reading
Educational information only, last refreshed 9/6/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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