Association of Family Cancer History With Pathogenic Variants in Specific Breast Cancer Susceptibility Genes

PURPOSE Family cancer history is an important component of genetic testing guidelines that estimate which patients with breast cancer are most likely to carry a germline pathogenic variant (PV). However, we do not know whether more extensive family history is differentially associated with PVs in specific genes. METHODS All women diagnosed with breast cancer in 2013-2017 and reported to statewide SEER registries of Georgia and California were linked to clinical genetic testing results and family history from two laboratories. Family history was defined as strong (suggestive of PVs in high-penetrance genes such as BRCA1/2 or TP53, including male breast, ovarian, pancreatic, sarcoma, or multiple female breast cancers), moderate (any other cancer history), or none. Among established breast cancer susceptibility genes ( ATM, BARD1, BRCA1, BRCA2, CDH1, CHEK2, NF1, PALB2, PTEN, RAD51C, RAD51D, and TP53), we evaluated PV prevalence according to family history extent and breast cancer subtype. We used a multivariable model to test for interaction between affected gene and family history extent for ATM, BRCA1/2, CHEK2, and PALB2. RESULTS A total of 34,865 women linked to genetic results. Higher PV prevalence with increasing family history extent ( P < .001) was observed only with BRCA1 (3.04% with none, 3.22% with moderate, and 4.06% with strong history) and in triple-negative breast cancer with PALB2 (0.75% with none, 2.23% with moderate, and 2.63% with strong history). In a multivariable model adjusted for age and subtype, there was no interaction between family history extent and PV prevalence for any gene except PALB2 ( P = .037). CONCLUSION Extent of family cancer history is not differentially associated with PVs across established breast cancer susceptibility genes and cannot be used to personalize genes selected for testing.

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Development and Validation of a Clinical Polygenic Risk Score to Predict Breast Cancer Risk

JCO Precision Oncology ◽

10.1200/po.19.00360 ◽

2020 ◽

pp. 585-592 ◽

Cited By ~ 1

Author(s):

Elisha Hughes ◽

Placede Tshiaba ◽

Shannon Gallagher ◽

Susanne Wagner ◽

Thaddeus Judkins ◽

...

Keyword(s):

Breast Cancer ◽

Breast Cancer Risk ◽

Cancer Risk ◽

Cancer Susceptibility ◽

Breast Cancer Susceptibility ◽

Susceptibility Genes ◽

Cancer History ◽

Pathogenic Variants ◽

Cancer Susceptibility Genes ◽

Breast Cancer Susceptibility Genes

PURPOSE Women with a family history of breast cancer are frequently referred for hereditary cancer genetic testing, yet < 10% are found to have pathogenic variants in known breast cancer susceptibility genes. Large-scale genotyping studies have identified common variants (primarily single-nucleotide polymorphisms [SNPs]) with individually modest breast cancer risk that, in aggregate, account for considerable breast cancer susceptibility. Here, we describe the development and empirical validation of an SNP-based polygenic breast cancer risk score. METHODS A panel of 94 SNPs was examined for association with breast cancer in women of European ancestry undergoing hereditary cancer genetic testing and negative for pathogenic variants in breast cancer susceptibility genes. Candidate polygenic risk scores (PRSs) as predictors of personal breast cancer history were developed through multivariable logistic regression models adjusted for age, cancer history, and ancestry. An optimized PRS was validated in 2 independent cohorts (n = 13,174; n = 141,160). RESULTS Within the training cohort (n = 24,259), 4,291 women (18%) had a personal history of breast cancer and 8,725 women (36%) reported breast cancer in a first-degree relative. The optimized PRS included 86 variants and was highly predictive of breast cancer status in both validation cohorts ( P = 6.4 × 10−66; P < 10−325). The odds ratio (OR) per unit standard deviation was consistent between validations (OR, 1.45 [95% CI, 1.39 to 1.52]; OR 1.47 [95% CI, 1.45 to 1.49]). In a direct comparison, the 86-SNP PRS outperformed a previously described PRS of 77 SNPs. CONCLUSION The validation and implementation of a PRS for women without pathogenic variants in known breast cancer susceptibility genes offers potential for risk stratification to guide surveillance recommendations.

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