Approximately 10% of breast cancers are hereditary, meaning they are caused by a single gene mutation that is being passed along through the generations of a family. When it comes to hereditary breast cancer, many of us have heard of the BRCA1/2 genes, which are genes that are associated with a high risk for breast, ovarian, and other cancers in individuals with an inherited mutation. But there are other lesser-known genes, like PALB2 for example, that are also important in the discussion of hereditary breast cancer.