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RESOURCE LIBRARY

The genetic-diagnostics reading desk

Plain-language explainers on hereditary-cancer testing — from swab to sequencer — sourced to NCI, ACMG, NCCN and the peer-reviewed literature. Educational only, never a substitute for a clinician or genetic counsellor.

~5–10%
of breast cancers are hereditary (germline)
NCI
5
ACMG tiers, from Pathogenic to Benign
ACMG/AMP 2015
>90%
probability threshold for a "Likely Pathogenic" call
ACMG/AMP 2015
~30 mo
DNA stability at room temperature in a saliva kit
DNA Genotek
The PROMPT registry was built to follow people with variants in lesser-characterised panel genes, so that patients, physicians and researchers could understand those risks more clearly. We carry that spirit forward in plain language — and we do not enrol.
PROMPT Registry · research desk

How we use real numbers

Our editorial standard is to attach a figure to its source and a range where the science is still settling. A representative slice of the data you'll meet across the Articles:

GenePenetrance bandIndicative lifetime riskNote
BRCA1High (>50%)~55–72%Penetrance to age 80 ~61% in cohort data
BRCA2High (>50%)~45–69%Penetrance to age 80 ~63% in cohort data
PALB2High–moderate~35–53%Risk rises with family history
CHEK2Moderate (20–50%)~15–35%≈2-fold over population baseline
ATMModerate (20–50%)~15–35%≈2-fold over population baseline

Table 1. Indicative lifetime breast-cancer risk by germline gene, with the penetrance band each falls into. Risks are population-and-context dependent; family history shifts them. Figures are illustrative ranges from the peer-reviewed literature, not personal estimates.

From sample to readable variant

A second illustrative slice — typical collected DNA yield by sample type. Yields vary widely between individuals; these are central estimates from manufacturer and method-comparison data.

Saliva (OG-500, 2 mL)110 µg

avg ~110 µg; range ~15–300+ µg

Buccal swab3 µg

lower yield; convenient, less DNA

Blood (EDTA, per mL)30 µg

high, consistent; venepuncture required

A taste of the Glossary

The full reference lives on the Glossary page; a few entries you'll lean on most:

VUS
Variant of uncertain significance — a change in DNA whose effect on cancer risk isn't yet established. It sits between Likely Benign and Likely Pathogenic on the ACMG scale and is not, by itself, an actionable result.
Penetrance
The share of people carrying a variant who actually develop the associated condition — "high" (>50%) for genes like BRCA1, "moderate" (~20–50%) for genes like CHEK2 and ATM.
Germline
A variant present in the egg or sperm and therefore in every cell, and heritable — as distinct from a somatic variant acquired in a tumour.
Category B / UN3373
The transport classification for most patient diagnostic specimens, shipped under packing instruction P650 with leak-proof primary and secondary receptacles, absorbent material and a rigid outer.
References
  1. [1]ACMG / AMP 2015. Richards S et al. Standards and guidelines for the interpretation of sequence variants. Genet Med. 2015.
  2. [2]ASCO / JCO 2016. Balmaña J, Digiovanni L, Gaddam P et al. Conflicting interpretation of genetic variants and cancer risk by commercial laboratories as assessed by the PROMPT registry. J Clin Oncol. 2016.
  3. [3]NCI. BRCA gene changes: cancer risk and genetic testing fact sheet. National Cancer Institute.
  4. [4]DNA Genotek. Oragene OG-500 product and stability specifications (DNA yield and room-temperature stability).

Start with the foundations

New to hereditary-cancer testing? The Guides walk the whole pathway, from collection to a readable variant. For anything about your own health, please speak with a clinician or genetic counsellor.