Breast Cancer Research | Full text | Familial relative risks for breast cancer by pathological subtype: a population-based cohort study

Conclusions

"We may conclude from our results that the FRR (familial relative risk) for breast cancer is significantly increased for each pathological subtype except TN tumours, although the numbers in the latter category were too small to draw definitive conclusions.
When analyzed by tumour subtype, a surprisingly high proportion of FRR (familial relative risk) for ER-negative disease is already explained.
We estimate that 32% of breast cancer FRR for ER-negative disease is explained by BRCA1 and BRCA2 mutations alone.
Patients carrying such mutations may be advised to undergo prophylactic therapies such as oophorectomy or mastectomy.
About 10% of the FRR for ER-positive disease is explained by 12 newly discovered SNPs, and the contributions of these SNPs to FRR are likely to be somewhat higher once the true causal variants are identified.
The construction of informative risk prediction models for ER-positive disease is particularly important as the risk of ER-positive disease can be reduced by chemoprevention such as tamoxifen.
It is possible that including novel (new) genetic variants associated with breast cancer susceptibility in models may improve risk prediction for subtype specific disease."