A protective allele rather than a risk one, and stronger for one subtype than for the disease as a whole. As with breast cancer, the genetics that changes decisions is BRCA — this is the other kind.
Ovarian cancer is difficult because it is usually found late: the early symptoms — bloating, feeling full quickly, pelvic discomfort, needing to pass urine more often — are common and vague, and no screening test has been shown to reduce deaths in the general population.
rs3814113 at 9p22.2, near BNC2, is a protective allele: an odds ratio of 0.82 (95% CI 0.79–0.86, P = 5.1 x 10-19) rather than a number above one. It came from a study that evaluated 507,094 genotyped SNPs plus about two million imputed ones in 1,817 cases and 2,353 controls, took the top 22,790 forward into 4,274 cases and 4,809 controls, and confirmed the strongest signal in a further 2,670 cases and 4,668 controls.
And it is not uniform across the disease. The association was strongest for serous ovarian cancer (OR 0.77, P = 4.1 x 10-21), which is the most common and most aggressive subtype. "Ovarian cancer" covers several diseases with different origins and different genetics, and this variant is a reminder of it.
As on our breast cancer page, the important distinction is between this and clinical genetic testing. Pathogenic variants in BRCA1 and BRCA2, and in the mismatch repair genes of Lynch syndrome, raise ovarian cancer risk substantially and change real decisions: enhanced surveillance, risk-reducing removal of the tubes and ovaries at an appropriate age, PARP inhibitor eligibility in treatment, and testing for relatives.
Testing of the tumour and of the person is now standard practice at diagnosis in many health systems, precisely because the result changes treatment. A common variant with an odds ratio of 0.82 changes nothing.
Knowing the family history — ovarian, breast, bowel or endometrial cancer in close relatives, particularly at young ages — and telling a doctor about it, because that is what triggers a referral for the testing that matters. And taking persistent, new abdominal symptoms to a clinician rather than waiting for them to declare themselves.
The study. Song et al. evaluated 507,094 genotyped SNPs and approximately 2 million imputed SNPs in 1,817 cases and 2,353 controls from the UK, genotyped the top 22,790 in 4,274 cases and 4,809 controls of European ancestry from Europe, the USA and Australia, and identified 12 SNPs at 9p22 at P < 10-8. The strongest, rs3814113 (P = 2.5 x 10-17), was genotyped in a further 2,670 cases and 4,668 controls, giving a combined odds ratio of 0.82 (95% CI 0.79–0.86, P trend = 5.1 x 10-19). The association differed by histology and was strongest for serous tumours (OR 0.77, 95% CI 0.73–0.81, P trend = 4.1 x 10-21).
High-penetrance genetics. Germline pathogenic variants in BRCA1 and BRCA2 account for a substantial share of the familial excess and carry lifetime risks far above the population rate; Lynch syndrome genes add ovarian as well as endometrial and colorectal risk. Both change management — risk-reducing salpingo-oophorectomy timing, surveillance for relatives, and eligibility for PARP inhibitors in treatment — and germline plus tumour testing at diagnosis is standard in many systems. RAD51C, RAD51D and BRIP1 are established moderate-risk genes.
Screening. Trials of CA-125 with or without transvaginal ultrasound in the general population have not demonstrated a mortality reduction sufficient to support routine screening, and symptom-based awareness plus prompt investigation remains the practical approach outside high-risk groups.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about Ovarian Cancer comes down to these specific, well-studied positions — not a diagnosis.
Slightly, at the level of populations. An odds ratio of 0.82 for one common variant does not make anyone safe, does not change screening or symptom advice, and is not a reason to worry less about a family history.
No. BRCA1 and BRCA2 testing looks for rare variants that raise risk substantially and changes real decisions — surveillance, risk-reducing surgery, treatment eligibility, testing for relatives. This is a common variant that changes none of them.
Because "ovarian cancer" is several diseases with different origins. This variant's association is strongest for serous tumours, the most common and aggressive kind, and weaker across the disease as a whole.
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