PROJECT SUMMARY Despite dramatic improvements in Breast Cancer (BC) prognosis over the past two decades, major survival differences after diagnosis persist based on a number of clinical factors and tumor characteristics. However, even within similar molecular BC subtypes there are differences in survival, supporting that additional factors should be considered to better predict outcomes after diagnosis. Surprisingly, unlike risk models for first incident BC, current models for prediction of survival after a BC diagnosis and treatment do not incorporate host germline genetic variation. In addition, Black women experience a 40% higher mortality rate due to BC compared to their White counterparts. Further, they have been greatly underrepresented in genomic studies; so future clinical implementations of new precision medicine solutions based on germline genetic variation may exacerbate existing health disparities. This proposal aims to produce empirical evidence that will be an essential first step to improve BC prognosis based on appropriate clinical recommendations targeted to those with the highest risk of poor outcomes. In Aim 1a, I will investigate if a polygenic risk score (PRS) improves risk prediction of BC prognosis, over and beyond standard clinical markers and tumor characteristics in the Breast Cancer Family Registry (BCFR). Aim 1b will utilize the BCFR to examine the impact of adding a PRS to existing BC prognostic tools such as the Nottingham Prognostic Index (NPI), which incorporates information on tumor size, tumor grade, and lymph node involvement. In Aim 2a, I will examine if the PRS improves risk prediction for BC prognosis in the Women’s Circle of Health Follow-Up Study (WCHFS), a longitudinal study of Black BC survivors. Aim 2b will examine the impact of adding PRS to NPI using data from the WCHFS. My long-term goal is to translate epidemiologic findings into clinical care through more accurate risk assessment and risk-reducing strategies for outcomes after a cancer diagnosis. This K22 award will provide me with the necessary training and support to accomplish the following short-term goals: (1) obtain advanced skills in statistical genetics; (2) training in the translation of scientific research findings in the clinical context; and (3) professional development including learning the skills necessary to be a successful independent investigator. To achieve these goals, I have proposed a detailed career development plan, including taking short courses and workshops, attending national conferences, meetings with my advisory committee, and obtaining research experience by completing the proposed research aims. This K22 research will address critical knowledge and clinical translation gaps in identifying women who are the highest risk for poor BC prognosis. Given the increasing number of BC survivors and persisting BC survival differences for certain subgroups, this is a timely and important proposal.

PROJECT NARRATIVE Despite dramatic improvements in breast cancer (BC) prognosis over the past two decades, major survival differences after diagnosis persist, even within similar stage and molecular BC subtypes. This proposal aims to use what we know about risk of developing breast cancer, including genetics and clinical factors, to improve prediction of outcomes following a BC diagnosis and improve BC survivorship.