Last updated 2mo ago
Log in to add personal notes on this page.
A 50-year-old woman is diagnosed with breast cancer. Her mother had breast cancer at 55, and her maternal uncle had colorectal cancer. Genetic testing reveals a CHEK2 c.1100delC pathogenic variant.
AD; CHEK2 (checkpoint kinase 2)
- DNA damage checkpoint response
- c.1100delC founder variant common in Northern European populations
- Moderate-penetrance breast cancer gene
- Often hormone receptor-positive breast cancers
- Less severe phenotype than BRCA1/2
- c.1100delC variant creates truncated protein
- Confirmed by germline testing identifying a pathogenic CHEK2 variant, usually on a multigene cancer panel rather than single-gene testing
- The c.1100delC truncating variant is the most common pathogenic allele; missense variants (e.g., p.Ile157Thr) confer lower risk
- Distinguish moderate-penetrance CHEK2 from high-penetrance BRCA1/BRCA2, since management and cascade-testing counseling differ
- Enhanced breast surveillance (earlier mammograms, consider MRI)
- Colonoscopy starting age 40 or 10 years before youngest family diagnosis
- Risk-reducing mastectomy generally NOT recommended (lower penetrance)
- No RRSO recommendation
"CHEK2 = CHEst Kancer from Chr 22": CHEK2 is on chromosome 22 and is associated with breast (chest) cancer.
"CHEK-ERS" checkered pattern: CHEK2 is associated with ER-positive breast cancer. Get a CHEK-up for breast cancer.