A genetic test result is rarely the end of a story. A laboratory report listing a change in a gene such as BRCA1 only becomes useful when it can be set against thousands of other results: who else carries it, what cancers they developed, and how confident anyone can be that the change matters. Patient registries are the quiet infrastructure that makes that pooling possible. This article explains how a registry takes raw sequence data and helps turn it into the screening and prevention guidance a clinician can act on.
What a hereditary-cancer registry actually does
A registry is a structured database of consenting participants who share their genetic test results and health histories for research. The Prospective Registry of Multiplex Testing (PROMPT), an academic registry cited across ASCO and JCO literature, was built precisely because multigene panel testing was generating findings in genes whose cancer risks were poorly understood. Pooling those scattered results was the only way to study them at scale.
Registries do not diagnose. Their value is aggregate: by collecting many carriers of the same variant, they let researchers estimate how risky that variant really is, and how often it co-occurs with cancer. PROMPT itself is best understood as research heritage — a model for how shared data sharpens interpretation — rather than a service to enrol in for a result.
From a raw variant to a classified one
The pivotal step is classification. A laboratory does not simply report “mutation found.” It places each finding into one of five tiers defined by the 2015 American College of Medical Genetics and Genomics and Association for Molecular Pathology (ACMG/AMP) framework:
- Pathogenic — strong evidence the variant causes disease.
- Likely pathogenic — at least ~90% confidence it is harmful.
- Variant of uncertain significance (VUS) — not enough evidence either way.
- Likely benign — at least ~90% confidence it is harmless.
- Benign — strong evidence it is harmless.
The framework weighs 28 criteria — from very strong (PVS1) down through supporting evidence — including population frequency, computational predictions, and how often the variant is seen in affected families. That last category is where registry data feeds directly back in: case counts pooled across participants are part of the evidence that moves a variant out of limbo.
Why “uncertain” is so common — and how it resolves
VUS findings are frequent. In one multigene panel cohort, initial reports flagged a VUS for about 10.5% of patients, falling to 7.5% after reclassification — roughly a 28% reduction once more data accrued. In BRCA1 and BRCA2 specifically, fewer than 1% of patients carried a VUS, because those genes are so heavily studied. Reclassification is the engine of the system: across large laboratory cohorts, several percent of variants are reclassified over the years as evidence matures, much of it driven by improved computational modelling and accumulated case data of exactly the kind registries help collect.
Turning a classified result into guidance
Once a variant is classified as pathogenic, professional guidelines such as the NCCN translate gene-level risk into action. The magnitude of risk drives the intensity of the response:
| Gene | Penetrance tier | Illustrative breast-cancer signal |
|---|---|---|
BRCA1 | High | More than 55–70% lifetime breast-cancer risk; ovarian risk ~39–44% |
BRCA2 | High | Comparable elevated breast risk; ovarian risk ~11–17% |
PALB2 | Moderate–high | Odds ratio roughly 3.8–5.0 for breast cancer |
ATM, CHEK2 | Moderate | Enhanced screening; risk-reducing surgery generally not advised on the variant alone |
For comparison, about 13% of women in the general population develop breast cancer over a lifetime. A high-penetrance result may prompt earlier and additional imaging or discussion of risk-reducing surgery; a moderate-penetrance result more often means enhanced surveillance weighed against family history. A VUS, importantly, is not acted on as if it were pathogenic — management follows personal and family history instead.
The bottom line
Registries do not hand out diagnoses; they make individual results legible by pooling them. Aggregated carrier data feeds the ACMG/AMP classification process, classification feeds reclassification as evidence grows, and a settled classification feeds the guideline-based guidance a clinician uses. The lesson of registries like PROMPT is that one person’s result is most useful as part of a much larger, shared picture.
Educational explainer, not medical advice. For your own testing or results, speak with a clinician or genetic counsellor.