OBJECTIVES: I. Estimate the incidence of early genetic damage, defined by the presence of clonal hematopoiesis using the human androgen receptor assay (HUMARA), in pretreatment blood and bone marrow, apheresis, and two sequential post-treatment specimens from women with stage II/III breast cancer enrolled in SWOG-S9623. II. Detect genetic damage following dose-intensive adjuvant regimens for breast cancer by screening for the presence of defective DNA mismatch repair mechanisms and loss of heterozygosity using microsatellite instability assays. III. Estimate the incidence of myeloid lymphoid leukemia gene fusion transcripts in cases where either the HUMARA or microsatellite repeat assays are positive for clonal hematopoiesis. IV. Determine the frequency of RAS gene mutations (H-, K-, and N-RAS) following dose-intensive adjuvant regimens for breast cancer.