Advances in genetics related to the diagnosis and treatment of cancer have transformed the oncology specialty into one with more promising outcomes. Because of the Human Genome Project, the association between genetics and cancer is more clearly defined and healthcare professionals need to be prepared to integrate new genetics knowledge into clinical practice. This article reviews basic genetic information essential for oncology nurses in advanced practice. Application of genetic guidelines uses the model of multiple myeloma. Multiple myeloma is an example of a disease in which cytogenetics has become increasingly important for diagnosis, prognosis, and treatment. As the basis of knowledge in genetics continues to expand, oncology providers are transitioning to a paradigm in which cytogenetic elements carry more weight in diagnosis and treatment.