Genetic factors contribute to breast cancer risk:
- Pathogenic variants in BRCA1 or BRCA2 are examples of monogenic factors.
- So-called SNPs (single-nucleotide polymorphisms) are polygenic factors: sequence variants that individually have a minimal effect on breast cancer risk; their combined effect is called a polygenic risk score (PRS).
In the detection of high risk, PRS contributes in the following scenarios:
- Presence of a pathogenic variant in CHEK2 or ATM for which high-risk screening is not recommended per se
- Breast cancer prior to 45 years of age without evidence of a pathogenic variant in BRCA1, BRCA2, or PALB2
- BOADICEA calculations for positive family history without evidence of pathogenic variants.
Risk distribution for breast cancer as a function of PRS for different patient groups. Non-Carriers: distribution in the general population without pathogenic variants in BRCA or other genes. Risk distribution with pathogenic variant in one of the genes CHEK2, ATM, PALB2, BRCA1 or BRCA2 depending on PRS. (Adapted from Gallagher et al. JAMA Netw Open. 2020;3(7):e208501.doi:10.1001/jamanetworkopen.2020.8501).
Request Report Low und High
When should an analysis of PRS not be performed?
Without an analysis of monogenic factors such as pathogenic variants in BRCA1 and BRCA1, PRS may lead to a completely incorrect risk assessment, especially if the PRS suggests a low