Apolipoprotein E genotype and cognitive function in postmenopausal women with early-stage breast cancer.

PURPOSE/OBJECTIVES To examine the role of apolipoprotein E (APOE) genotype in the cognitive function of postmenopausal women with early-stage breast cancer prior to initiation of adjuvant therapy and over time with treatment. DESIGN Longitudinal, genetic association study. SETTING Urban university cancer center. SAMPLE Three cohorts of postmenopausal women: 37 women with breast cancer receiving chemotherapy and anastrozole, 41 women with breast cancer receiving anastrozole alone, and 50 healthy women. METHODS Cognitive function was evaluated three times during a 12-month period using a comprehensive neuropsychological test battery. Participants were genotyped and classified based on the presence or absence of at least one APOE e4 allele. Multiple linear regression was used to determine if APOE genotype accounted for observed variability in cognitive function data. MAIN RESEARCH VARIABLES APOE genotype, breast cancer treatment, and cognitive function. FINDINGS Performance or changes in performance on tasks of executive function, attention, verbal learning and memory, and visual learning and memory were found to be influenced by APOE genotype and/or interactions between APOE genotype and study cohort. CONCLUSIONS The results indicate that cognitive function in postmenopausal women with breast cancer is modified by APOE genotype and the combination of APOE genotype and treatment. IMPLICATIONS FOR NURSING APOE genotype, along with other biomarkers, may be used in the future to assist nurses in identifying women with breast cancer most at risk for cognitive decline.