Abstract PS4-03-03: Age-driven genomic differences in breast cancer: relevance for PI3K-pathway

Abstract Background The rising incidence of Breast cancer (BC) in young women requires further genomic characterization, as only a fraction carry a germline mutation. Given the growing interest in therapies targeting the phosphoinositide 3-kinase/AKT (PI3K/AKT), mammalian target of rapamycin (mTOR), and phosphatase and tensin homolog (PTEN) pathways, central to BC pathogenesis, we evaluated whether PI3K/AKT/mTOR pathway alterations and gene expression differed by age at BC diagnosis. Methods: In this analysis of patients’ tumor/germline whole exome DNA and RNA sequencing data from the Ohio State University Total Cancer Care registry, 71 profiled patients were young adults (YA) aged < 40 years, and 675 were non-YA aged ≥40 years. Descriptive statistics characterized the frequency and co-occurrence of BC-specific alterations and mRNA expression profiles by age groups. Results The prevalence of these BC-relevant mutations are reported in Table 1 Table: Prevalence of BC-relevant mutations by age cohort Mutation Age Group % of Patients with Mutation Fisher's Exact Test p-value (