Current advances in genetics have provided a better understanding of many diseases, including cancer, and will have an impact on oncology clinical practice in an unprecedented way. The molecular cytogenetic techniques of fluorescent in situ hybridization (FISH), comparative genomic hybridization (CGH), and spectral karyotyping (SKY) are providing tremendous insights into genetic information related to cancer by specifically illustrating chromosomal abnormalities that can occur in a patient's cancer cells. The application of these techniques allows for the development of molecular diagnostic tests may be applied to clinical material, which may help to improve the diagnosis and staging of a patient's tumor, particularly in small, premalignant lesions that often are equivocal and difficult to assess. An understanding of these genetic changes will provide a foundation of knowledge for oncology nurses that will lead to significantly improved detection methods, therapies, and disease prevention. As members of the healthcare team, oncology nurses must be knowledgeable about the rapid expansion of genetic information. Oncology nurses are in a unique position to translate this information to patients and their families and, ultimately, enhance comprehensive care through patient education and advocacy.