@mjay, thanks for taking the time to explain. I get your query now. Unfortunately, I don't have answers. Genetics and cancer is a relatively new field and so much to explore.

SNPs of genes associated with breast cancer can be used as a potential tool for improving cancer diagnosis and treatment planning. You can read more here (medical journal): http://journal.waocp.org/article_27798_4f54566a1f0205b00300b100f6e33d37.pdf

While not specific to single nucleotide polymorphisms (SNPs), you might be interested in this Mayo Expert Q&A
- Cancer-Fighting Foods https://connect.mayoclinic.org/webinar/cancer-fighting-foods/