While researchers may never know the exact cause of breast cancer, they do know the main risks and triggers of it. Among the list one of the top risk factors is having a high level of estrogen. The amount of estrogen your body produces is largely influenced by your genetics. This is one possible reason why women who have a first-degree relative(mother or sister) who has been diagnosed with breast cancer are two to three times more likely to develop the disease themselves.
Some differences in your genes are linked to cancer. While this does not automatically mean that you have cancer, it does put you at a significantly higher risk of developing it in the future. This is why genetic counseling is so important; it can help individuals to better understand their risks and to seek treatment. Speak with your primary care physician or gynecologist for more information on making a genetic counseling