Genetics and Genomics: A New Frontier in Oncology

Lea and Calzone have provided an outstanding overview of genetics and genomic research applicable to the subspecialty of oncology nursing. The ever-emerging discoveries in this discipline mandate that nurses understand the key concepts of genetics and genomics and their everyday application to comprehensive care of the oncology patient and family throughout all phases of the trajectory of cancer care.

All nurses need to be familiar with the document Essentials of Genetic and Genomic Nursing.[1] This resource emphasizes that all nurses should understand the role of both genetics and genomics in healthcare. Genetics is the study of individual genes and the ways in which their expression or dysfunction impacts the development of relatively rare single-gene disorders. Many mistakenly believe that genetics and genomics are interchangeable and that genetics explains how all disease, including cancer, develops.

Genomics is an exploding area of interest in oncology care and includes the study of all genes in the human genome together, including their interactions with each other and the environment, as well as the influence of psychosocial and cultural factors on the development of disease, such as cancer. Lea and Calzone provide numerous relevant clinical examples of applied genomics, describing how the science of genomics relates to personalized healthcare.

Nurses need to be able to explain basic concepts of genetics and genomics to patients and families. One area that often requires clarification involves the transmission of hereditary risk. Gene mutations can be inherited, spontaneous, or acquired. Inherited gene mutations, called germline mutations, are present in all body cells. They are passed on from parent to child in reproductive cells (the egg and sperm), and are present in all of the cells in that child's body when the body cells reproduce. A spontaneous mutation can occur in individual eggs or sperm at conception. A person who has the new, spontaneous mutation is at risk of passing the mutated gene to his or her children.

Acquired mutations, also called somatic mutations, occur in body cells other than egg or sperm. They involve changes in DNA that take place after conception, during a person's lifetime. Acquired mutations result from cumulative changes in body cells other than egg or sperm, called somatic cells. Somatic gene mutations are passed on when the cells they contain reproduce. Frequently patients will state that they underwent genetic testing, thinking that such testing implies hereditary risk, when in reality they may have had testing of their tumor, such as HER2 (human epidermal growth factor receptor 2) testing to direct treatment decisions. Nurses need to be able to explain basic genetic concepts in terms that can be understood by patients and families.

It is important for oncology nurses to recognize when a person may potentially have a hereditary (germline mutation) risk for developing cancer and when it is appropriate to refer that individual and family for further genetic risk assessment, evaluation, and possibly genetic testing. This relatively small subset of individuals and families should be referred to a credentialed genetics professional for evaluation.[2] Clearly, identification of a germline mutation and family members at significantly high risk for developing cancer can result in targeted and potentially effective prevention and early detection strategies, and this traditional application of genetics is essential to good oncology nursing.

Learning about the influence of genetic and genomic factors on health and disease is resulting in earlier diagnosis, more effective and individualized prevention and treatment of disease, better response to treatments, and improved health. In their article, Lea and Calzone highlight many aspects and applications of genomics in cancer screening and management. Nurses are increasingly being called upon to apply genetic- and genomic-based approaches and technologies in client care. The significant impact of genomics on oncology care has arrived.

Implementation of genomics in oncology care potentially impacts a much larger segment of the oncology patient population, and on many different levels. The authors provide several excellent examples of how genomics is influencing cancer screening, especially in the area of colorectal cancer. Undoubtedly, in the future genomics-based screening will be utilized to manage other cancer types as well.

Genomics frequently guides cancer treatment decisions. It is no longer considered investigational. For example, the NCCN (National Comprehensive Cancer Network) Guidelines for the Treatment of Breast Cancer discuss the role of microarray analysis in decisions related to whether or not offer adjuvant therapy to selected women with breast cancer, based on the risk profile from microarray analyses such as Oncotype DX,[3] a decision-making tool discussed by Lea and Calzone in their article.

Oncology nurses also need to rethink how genomics affects care. An emerging example includes the drug tamoxifen. Oncology nurses have administered this drug for treatment and more recently for prevention, and have provided tamoxifen-related patient education to breast cancer patients for decades. Genomics may be rapidly changing how this medication is utilized, and which patients are selected to receive tamoxifen as treatment. Data are emerging about the influence of the major cytochrome P450 2D6 (CYP2D6) genotypes and CYP2D6 inhibitors on tamoxifen metabolism and effectiveness.[4] Although routine testing for CYP2D6 is not yet justified by the current evidence, research continues. In the future it will be possible to test for a panel of genes that promote or inhibit drug metabolism and determine, based on specific genetic mutations, whether a patient is likely to benefit from a given drug.

Lea and Calzone also describe how targeted therapies such as cetuximab (Erbitux) or trastuzumab (Herceptin) determine specific treatment strategies. Oncology nurses regularly administer these treatments, assess and manage the side effects associated with targeted therapy, and provide patient education. These therapies are only available because of genomics. It should expected that each nursing curriculum preparing nurses for practice at any level will incorporate genetic and genomic topics and learning experiences into existing classes to adequately prepare nurses for the future. The Essential Nursing Competencies and Curricula Guidelines in Genetics and Genomics includes a comprehensive listing of resources for nurse educators.

Presently only a limited number of continuing education programs are designed to prepare nurses already in practice to incorporate genetics information into current practice. Continuing education is a beginning step to assure that all practicing nurses will be able to translate new genetic and genomic knowledge and skills into healthcare and patient education. Many seasoned nurses need beginning education on genetics and genomics.

The International Society of Nurses in Genetics (ISONG) has developed a mechanism for the credentialing of nurses who specialize in genetics. Review of the nurse's qualifications by examining a comprehensive portfolio that illustrates specific education and clinical experience in genetic nursing practice is the primary mechanism utilized to measure knowledge, skill, and clinical competence.[5,6] Genetics nursing practice is credentialed at both basic and advanced levels. Genetics nursing practice at the basic level includes assessment to identify risk factors, planning of care, interventions such as information or services, and evaluation of the client for referral to genetic services. Advanced nurses who practice in genetics provide genetic counseling, case management, consultation, and evaluation of clients, families, resources, and programs.

Nearly all components of the nursing process offer opportunities for the nurse to identify genetic information that may be helpful to the care of individual patients and families. Examples include assessing family and reproductive history to identify the potential of high risk for an illness (such as breast or colon cancer); providing screening recommendations; and interpreting diagnostic test results and the impact of the results on therapy choices and patient and family education. Continuing efforts will need to address the spectrum of genetics that all nurses will need to integrate into their practice. The Essentials of Genetic and Genomic Nursing provides an excellent starting place for considering the role of genetics and genomics in nursing.

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Financial Disclosure: The authors have no signifi cant fi nancial interestor other relationship with the manufacturers of any products orproviders of any service mentioned in this article.

References

1. Consensus Panel on Genetics/Genomic Nursing Competencies: Essentials of Genetic and Genomic Nursing: Competencies, Curricula Guidelines, and Outcome Indicators, edition 2. Available at: www.genome.gov/Pages/Careers/HealthProfessionalEducation/geneticscompetency.pdf. Silver Spring, MD, American Nurses Association, 2009. Accessed on January 3, 2010.

2. Mahon SM: Cancer genomics: Advocating for competent care for cancer families. Clin J Oncol Nurs 13(4):373–376, 2009.

3. NCCN Clinical Practice Guidelines in Oncology: Breast Cancer, V.1.2010. Available at: www.nccn.org. Accessed on January 5, 2010.

4. Kuderer NM, Peppercorn J: CYP2D6 testing in breast cancer: Ready for prime time? Oncology (Williston Park) 23(14):1223–1232, 2009.

5. Monson RB: Genetics Nursing Portfolios: A New Model for Credentialing. Silver Spring, MD, American Nurses Association, 2005.

6. International Society of Nurses in Genetics (ISONG): Genetics/ Genomics Nursing: Scope & Standards of Practice. Silver Spring, MD, American Nurses Association, 2007.