For each case, basic biomarkers were reviewed on immunohistochemistry (IHC) slides. All IHC staining procedures were performed using BenchMark XT autostainer (Ventana Medical Systems, Tucson, USA) with an UltraView detection kit (Ventana Medical Systems). The following antibodies were used: ER (1:100; clone SP1; Labvision, Fremont, USA), PR (1:70; PgR 636; Dako, Carpinteria, USA), HER2 (ready to use; clone 4B5; Ventana Medical Systems), p53 (1:600; D07; Dako), and Ki-67 (1:250; MIB-1; Dako). ER and PR were considered positive if there were at least 1% positive tumor nuclei. For ER and PR, expression level was scored in 10% increments, and their Allred scores were calculated [13 (link)]. HER2 expression was scored according to 2013 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines [14 (link)]. For Ki-67 proliferation index, positive staining in 20% or more tumor cells was regarded as a high index. As biomarker status can change after neoadjuvant chemotherapy (especially PR and Ki-67 proliferation index) [15 (link)16 (link)], we used the biomarker data from the pre-treatment needle biopsy specimen in patients who received neoadjuvant chemotherapy.