Most efforts to identify individuals who have a hereditary predisposition for developing breast cancer had focused on the BRCA1 and BRCA2 genes. Less common susceptibility genes also are associated with increased risk for developing breast cancer, but until recently have often gone undetected. With the advent of next generation sequencing (NGS), many families with suspected hereditary risk are undergoing testing for multiple genes associated with increased cancer risk (Mahon, 2013a). One gene that is commonly included on NGS hereditary breast cancer panels is CHEK2. Increasingly, oncology nurses will encounter patients and families affected with mutations on this gene and need to understand the implications it has for screening and treatment.