- Design
- Prospective case-cohort proteomic study with external evaluation
- Population
- 982 incident prostate cancer cases and 1573 subcohort participants in EPIC
- Primary outcome
- Incident overall and aggressive prostate cancer
- Effect
- KLK3 HR 2.28 (1.96 to 2.65) per SD; 12 proteins linked to cancer >15 years later
Within the European Prospective Investigation into Cancer and Nutrition, a case-cohort study profiled over 6000 plasma proteins in baseline samples from 982 men who later developed prostate cancer and 1573 subcohort participants.
Besides KLK3, the gene for PSA (HR 2.28 per standard deviation), proteins including ACP3 and FLT4 were associated with overall risk, seven with aggressive disease, and 12 with cancers diagnosed more than 15 years after blood draw. Circulating products of driver genes such as ERBB3, KRAS and NRAS were associated with future aggressive disease. Some findings replicated in a US cohort and had genetic support.
This is discovery science. No protein panel is ready for screening, and PSA with risk-stratified MRI remains the clinical pathway.
- Do not order proteomic panels for prostate cancer risk; none is validated for clinical use.
- Continue PSA testing with shared decision-making and MRI before biopsy where available.
- Note that PSA itself carried the strongest association, years before diagnosis.
- Expect validation studies before any of these proteins enters screening.
Why it matters
It suggests signals of aggressive prostate cancer may be detectable in blood many years ahead.
Don't overread it
External replication was incomplete; these are candidate risk markers, not diagnostic tests.
The statistics, in plain English
A hazard ratio of 2.28 per standard deviation means each step up in KLK3 level was associated with roughly double the rate of later diagnosis. Testing thousands of proteins raises the chance of false positives, which is why replication matters.
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