RecruitingDiagnostic testEXActDNA-003 / NSABP B-64: Study of Molecular Residual Disease Detection in Breast Cancer (MRD)The EXActDNA-003 study will prospectively enroll participants who are planning to undergo chemotherapy for high-risk, early breast cancer, who are willing to provide tissue and blood specimens for circulating tumor DNA (ctDNA) analysis. Participants will be followed for up to 5.5 years.