Risks, brca 1 & 2, are known, other are not, but familial clusters (mother, aunt sister) point to risk but the actual cause and function of the genetics are mysterious.
We humans have a hard time with "risk". Some with no risk delvelop a cancer
; others with high risk do not. The statistical facts work epidemiologicallyfor populations, but are not informative for an individual. They do cause worr.