Transcript 226870
Acquired chromosomal changes in lymphocytes are associated with cognitive dysfunction (CD) prior to chemotherapy in women with breast cancer (BC) Debra E. Lyon, PhD, RN, FNP-BC, FAAN Judith B. Collins and Joseph M. Teefey Distinguished Professor Professor and Chair, Department of Family and Community Health Nursing School of Nursing, Virginia Commonwealth University Research Team Colleen Jackson-Cook, PhD MPI Cytogeneticist Lynne Elmore, PhD Cell biologist Ronald K. Elswick, PhD Biostatistician Nancy McCain, RN, DNS Nurse scientist Angela Starkweather, RN, PhD Nurse scientist Sponsor: R01NR012667, Lyon & Jackson-Cook MPI Oct 2010-July 2015: R01 ES12074 (Jackson-Cook) Background In 2012, 226,870 new breast cancer (BC) cases in women are expected to be diagnosed in the United States (Siegal, Naishadham, & Jemal, 2012). Most women are diagnosed in the early stages of the disease (Stage I and II) and 90% of these individuals can expect to survive at least 5 years (Siegel, Naishadham, & Jemal, 2012). Increased survival leading to focus on short and long-term effects Improvements in adjuvant chemotherapy and targeted hormonal therapies have contributed to increased survival for women with breast cancer. However, these treatments, and, perhaps the cancer itself, contribute to a number of distressing short and long-term side-effects and symptoms. Even though mortality rates have decreased, breast cancer patients may experience a number of life-altering and debilitating side effects of breast cancer and its treatment that may persist in some women long after active treatment has ended. Long-term effects: Focus on Cognitive Dysfunction First noted by patients with breast cancer and commonly referred to as “chemobrain,” cognitive dysfunction has been examined from a subjective (patient-report) and objective (neuropsychological instrumentation and examination) perspective. However, research supporting the relationship of BC and BC treatments with cognitive dysfunction, while an area of intense interest, is not yet definitive (Wefel, Vardy, Ahles, & Schagen, 2011). Current Theories are Incomplete Although a biological model that includes inflammation as an initiating step leading to PNS has partial empirical support, the evidence, to date, is not sufficient to conclude that peripheral inflammatory mechanisms are a complete or sufficient mechanism for treatment-related symptoms or persistent symptoms in survivors (Koppelman et al., 2012). Since most inflammatory molecules, such as cytokines, are relatively shortlived, the mechanism(s) for how these changes could lead to long-term symptoms that persist and are embedded in an individual’s biological “memory” beyond the time of chemotherapy treatment has been enigmatic (Esteller, 2008). Epigenomic Modifications? One possible means for biologically “remembering” the effects of BC and/or it treatments would be if they resulted in DNA-based changes in the individual’s somatic cells. These acquired changes could result from either epigenomic modifications (which encompass alterations in DNA methylation patterns, modifications of histone proteins, and/or chromatin structure) (Feinberg, 2008) or genomic changes (which include, but are not limited to acquired chromosomal instability). Acquired Chromosomal Instability Cancer and psychiatric conditions are associated with micronuclei frequency in peripheral blood lymphocytes (Cardinale et al., 2011). Methods • We have initiated a 5 year grant, with a 2-year longitudinal component. To date, we have studied 25 women (ages 29-67) with earlystage (stage I n=5; IIA n=10; IIB n= 9; IIIA n=1) BC and have determined acquired changes in lymphocyte chromosomal abnormalities (cytokinesis-block micronucleus assay) at base-line. Design • Comparisons were made to age-matched healthy individuals from a twin registry (MidAtlantic Twin Registry) . Cognitive function was assessed using the Central Nervous System-Vital Signs Test (CNSVS). Results • The mean micronuclei frequencies (MNF) in women with BC prior to treatment (5% ± 1.6%) was significantly higher than the mean MNF in age-matched, healthy negative controls (1.6% ± .87%) (p<.0001). Several domains of cognitive function including reaction time, complex attention, cognitive flexibility and executive functioning were correlated with MNF (p< 0.05). Chromosomal Instability • These data suggest that women with BC may have elevated levels of chromosomal instability in lymphocytes prior to chemotherapy and that these genomic alterations may be correlated with a subset of cognitive dysfunction domains in women with breast cancer. Conclusion • Further examination of chromosomal changes as potential mechanisms directly contributing to or mediating the acquisition of PN symptoms is warranted. References Cardinale, F., Bruzzi, P., & Bolognesi, C. (2011). Role of micronucleus test in predicting breast cancer susceptibility: a systematic review and meta-analysis. British Journal of Cancer. Esteller, M. (2008). Epigenetics in cancer. New England Journal of Medicine, 358(11), 1148-1159. Feinberg, A. (2008). Epigenetics at the epicenter of modern medicine. JAMA: the journal of the American Medical Association, 299(11), 1345. Koppelmans, V., Breteler, M. M. B., Boogerd, W., Seynaeve, C., Gundy, C., & Schagen, S. B. (2012). Neuropsychological Performance in Survivors of Breast Cancer More Than 20 Years After Adjuvant Chemotherapy. Journal of Clinical Oncology. doi: 10.1200/jco.2011.37.0189 Migliore, L., Coppedè, F., Fenech, M., & Thomas, P. (2011). Association of micronucleus frequency with neurodegenerative diseases. Mutagenesis, 26(1), 85. Siegel, R., Naishadham, D., & Jemal, A. (2012). Cancer statistics, 2012. CA: A Cancer Journal for Clinicians. Wefel, J. S., Vardy, J., Ahles, T., & Schagen, S. B. (2011). International Cognition and Cancer Task Force recommendations to harmonise studies of cognitive function in patients with cancer. The Lancet Oncology.