Multimodal Liquid-Biopsy Omics Biomarkers of Treatment Response in Breast Cancer

This single-center cohort study integrates humoral immune response profiling (Phage ImmunoPrecipitation Sequencing, PhIP-seq) with circulating cell-free DNA (cfDNA) genomic and epigenomic features, exosome transcriptomics, and plasma metabolomics to discover and validate liquid-biopsy biomarkers of treatment response in breast cancer. The study comprises four cohorts: (1) a retrospective pan-cancer cohort of approximately 1,000 patients with solid malignant tumor, using archived residual serum/plasma to construct a pan-cancer antigen repertoire and cfDNA mutational/methylation atlas, with priority given to patients who had available Whole Exome Sequencing (WES) data; (2) a prospective cohort of 800 women with non-metastatic (M0) breast cancer receiving standard neoadjuvant chemotherapy (NAC); (3) a prospective cohort of 100 women with metastatic (M1) breast cancer receiving standard systemic therapy; and (4) a control group of 100 individuals, including patients with benign breast disease (breast fibroadenoma) and healthy volunteers. The primary objective is to identify biomarkers-autoantibody repertoires, cfDNA mutation clearance, methylation reprogramming, exosome transcripts, and metabolic signatures-associated with pathological complete response (pCR) to NAC, and to develop predictive models where feasible.