Updated project metadata. Breast cancer is the most frequently diagnosed female cancer accounting for 23 % of the total cases and the second leading cause of cancer mortality in the world, particularly in western countries. Since GEPARDUO trial reported the therapeutic benefit of combined doxorubicin and cyclophosphamide regimen in sequential administration with docetaxel, the combination regimen has become a standard therapeutic strategy in neoadjuvant systemic therapy for patients with operable breast cancers regardless of an intrinsic subtype. Although approximately 70% of entire patients are currently receiving the chemotherapy regimen, pathologic complete response (pCR) rate is still low, ranging from 23% to 32.7% due to the high heterogeneity of breast cancers. Therefore, the need for a marker predictive of response to a particular cytotoxic regimen, especially before neoadjuvant chemotherapy, is becoming all the more necessary to optimize therapeutic efficacy and to avoid unnecessary complications caused by systemic therapy. In the study, here we generated the first high-coverage proteomic data for needle biopsy FFPE sample being characterized with identical clinical conditions including chemotherapeutic regimens and the stage classification.