In this study, we evaluated the concordance of targeted sequencing results between paired ctDNA and tumor samples from early breast cancers scheduled for curative surgery with or without adjuvant therapy. If high concordance was observed, pre-operative ctDNA testing could serve as a non-invasive surrogate for variants meant to be revealed after definite surgery. On the other hand, poor concordance may hamper wide clinical absorption of liquid biopsy early breast cancer. The study VGH-TAYLOR: Comprehensive precision medicine research on the heterogeneity of Taiwanese breast cancer Patients, consisted of three years enrollment and approximately four years follow-up after enrollment. Individual subject was assigned into 3 groups based on the staging and therapy before and/or after surgery. Molecular profiling and potential biomarkers were determined using Oncomine Comprehensive Assay v3 from FFPE tissues and Oncomine Breast cfDNA Assay v2 from plasma. Common genes interrogated by both ctDNA and TMO comprehensive assay were identified, and concordance-between paired targeted sequencing results from the same individuals were reported. The mutation landscape of initial 612 patients interrogated with the Oncomine Breast cfDNA assay v2; 239 out of 612 patients reported at least one mutation (39%). Among 246 patients assayed for both ctDNA and tumor tissue, cfDNA assay detected 73 (29.6%) and TMO comprehensive assay detected 201 (81 .7%) breast cancers with at least one variant. Sixty-seven (25.6%) were tested positive for both liquid and tissue assays. Although only one-quarter of patients were positive for both cfDNA and TMO comprehensive assays from the same subject, the most prevalent mutant genes from both platforms were TP53 (68.3%) and KRAS (53.5%), both were well-known drivers in cancers. Our study showed that tumor should be the preferred source and targeted sequencing and 4% variants wound be revealed from liquid biopsy.