What you carry at this position in your DNA and what research says about it.
Stomach Cancer Risk: 8/10 evidence, 53 publications.
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Sample genotype (not yours): C/C
Lower Stomach Cancer Risk but Higher Ulcer Risk
This genotype is associated with a lower risk of stomach and bladder cancers. However, it carries a higher susceptibility to developing duodenal and peptic ulcers.
What this genotype means: Lower risk of stomach and bladder cancers; Higher risk of duodenal and peptic ulcers.
Sample genotype (not yours): C/T
Typical Risk of Stomach Cancer and Ulcers
This genotype carries one copy of each allele, resulting in typical, intermediate risks for both stomach cancer and ulcers. It represents the most common genetic profile globally.
What this genotype means: Typical baseline risk for stomach and bladder cancers; Typical baseline risk for peptic and duodenal ulcers.
Sample genotype (not yours): T/T
Higher Stomach Cancer Risk but Lower Ulcer Risk
This genotype is linked to an increased risk of stomach and bladder cancers. Conversely, it provides a protective effect against developing duodenal and peptic ulcers.
What this genotype means: Increased risk of stomach and bladder cancers; Lower risk of duodenal and peptic ulcers.
Gene function and biological role
Gene Function: The PSCA gene encodes the prostate stem cell antigen, a glycosylphosphatidylinositol-anchored cell surface glycoprotein. Despite its name, this protein is expressed not only in the prostate but also in the stomach, bladder, and other mucosal tissues. It belongs to the Thy-1/Ly-6 family and is thought to play a role in cell adhesion, proliferation, and immune signaling. In the stomach, PSCA helps maintain the integrity of the gastric mucosal lining. Variations in this gene can alter its expression levels, impacting how the tissue responds to chronic inflammation and cellular stress.
Variant Impact: The rs2294008 variant is a single nucleotide polymorphism located in the 5 prime untranslated region of the PSCA gene, which functions as an alternative translation start site. The T allele creates an upstream start codon that alters the N-terminal sequence of the protein, affecting its intracellular transport and cell surface localization. This molecular shift influences how the protein is expressed on the surface of epithelial cells in the bladder and stomach. Consequently, this single letter change acts as a genetic pivot, modifying susceptibility to both mucosal cancers and inflammatory ulcer diseases.
Key Insight: This variant represents a classic evolutionary trade-off where the allele that increases stomach cancer risk actually protects against painful duodenal ulcers.
Location: PSCA. Chromosome 8 · 8q24.3 · 142.7 Mb
Estimated prevalence by population
Global 30.5%; European 29.9%; African 34.4%; East Asian 42.0%; South Asian 34.1%; Americas 23.7%; Ashkenazi 23.4%; Finnish 24.3%; Middle Eastern 27.8%; Amish 37.3%.
Estimated CC genotype frequency.
Global 49.2%; European 49.6%; African 48.5%; East Asian 45.6%; South Asian 48.6%; Americas 50.0%; Ashkenazi 49.9%; Finnish 50.0%; Middle Eastern 49.9%; Amish 47.5%.
Estimated CT genotype frequency.
Global 20.3%; European 20.6%; African 17.1%; East Asian 12.4%; South Asian 17.3%; Americas 26.4%; Ashkenazi 26.7%; Finnish 25.7%; Middle Eastern 22.4%; Amish 15.1%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Cancer & Oncology
Gastrointestinal Cancers
Gastric Cancer. Evidence: 8/10. Source: PMID 26098866. Lower Risk.
Urologic Cancers
Bladder Cancer. Evidence: 8/10. Source: PMID 19648920. Lower Risk.
Organ Systems
Digestive & Gut Disorders
Duodenal Ulcer. Evidence: 9/10. Source: PMID 22387998. Increased Risk.
Peptic Ulcer. Evidence: 9/10. Source: PMID 38036781. Increased Risk.
Showing effects for C/T genotype
Gastric Cancer. Evidence: 8/10. Source: PMID 26098866. Typical Risk.
Bladder Cancer. Evidence: 8/10. Source: PMID 19648920. Typical Risk.
Duodenal Ulcer. Evidence: 9/10. Source: PMID 22387998. Typical Risk.
Peptic Ulcer. Evidence: 9/10. Source: PMID 38036781. Typical Risk.
Showing effects for T/T genotype
Gastric Cancer. Evidence: 8/10. Source: PMID 26098866. ~1.2x Higher Risk.
Bladder Cancer. Evidence: 8/10. Source: PMID 19648920. ~1.14x Higher Risk.
Duodenal Ulcer. Evidence: 9/10. Source: PMID 22387998. Lower Risk.
Peptic Ulcer. Evidence: 9/10. Source: PMID 38036781. Lower Risk.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Possessing two copies of the C allele is highly protective against stomach and bladder cancers. This protective effect is thought to stem from normal regulation of the PSCA protein, which prevents abnormal cell proliferation in mucosal tissues. However, this same genetic profile increases the risk of developing duodenal and peptic ulcers. Researchers believe that the C allele leads to a stronger inflammatory response in the presence of Helicobacter pylori infection. While this robust immune response helps clear damaged cells and prevents long-term cancerous changes, it makes the tissue more prone to painful ulceration. This represents a classic evolutionary trade-off where a genotype protects against a severe late-life disease at the cost of a common, manageable inflammatory condition. Understanding this balance can help guide personalized approaches to digestive health and symptom management.
Lower risk of stomach and bladder cancers; Higher risk of duodenal and peptic ulcers.
Sample genotype: CT (Heterozygous)
An intermediate genetic profile consisting of one C allele and one T allele results in typical risk levels for both mucosal cancers and peptic ulcers. Because this genotype is highly common, it serves as the baseline or typical risk level in most clinical studies. The presence of a single T allele slightly increases the risk of stomach and bladder cancers compared to the C/C genotype, but to a lesser degree than carrying two copies of the T allele. Conversely, the single C allele maintains a moderate risk of duodenal and peptic ulcers. This balanced genetic state means that overall health outcomes are heavily influenced by environmental factors. Lifestyle choices, diet, smoking habits, and Helicobacter pylori infection status play a dominant role in determining actual disease risk. Maintaining routine gastrointestinal health screenings and managing acid reflux or stomach pain remain standard recommendations.
Typical baseline risk for stomach and bladder cancers; Typical baseline risk for peptic and duodenal ulcers.
Sample genotype: TT (Homozygous)
Inheriting two copies of the T allele is a well-established risk factor for stomach and bladder cancers. The T allele alters the PSCA protein's structure and localization, which can promote tumor growth and reduce the body's natural defenses against mucosal malignancies. This risk is particularly pronounced in the presence of chronic Helicobacter pylori infection, which can lead to atrophic gastritis. Interestingly, this same genetic change is highly protective against duodenal and peptic ulcers. The altered protein expression appears to dampen the localized tissue-damaging inflammatory response that typically causes ulcers. This genetic profile highlights how a single variant can have opposing effects on different diseases within the same organ system. While the risk of cancer is elevated, proactive lifestyle measures and regular medical checkups can help mitigate these genetic predispositions.
Increased risk of stomach and bladder cancers; Lower risk of duodenal and peptic ulcers.
Variants with shared genetic architecture
rs13361707 · PRKAA1 Gene · Chr 5 · Stomach Cancer Risk
rs1495741 · NAT2 Gene · Chr 8 · Drug and Toxin Metabolism
rs17138478 · HNF1B Gene · Chr 17 · Stomach Cancer Risk
Content updated August 2026.
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