IHC and in-situ hybridisation were performed as described elsewhere39 (link),40 (link). Briefly, the following antibodies were used for IHC staining to determine the subtype: ER (1D5; DAKO, Copenhagen, Denmark), progesterone receptor (PgR; PgR636; DAKO), and HER2 (HercepTest; DAKO). Specimens with a nuclear staining rate ≥1% were considered HR-positive (ER and PgR). HER2 amplification was automatically stained (BenchMark® XT; Ventana Medical Systems, Tucson, Arizona, USA) with dual in-situ hybridisation (DISH; INFORM HER2 Dual ISH DNA Probe Cocktail Assay; Roche, Basel, Switzerland). Patients with ‘HER2 IHC-score 3+’ or ‘HER2 IHC-score 2+ and those positive for HER2 amplification by DISH’ were defined as HER2-positive type. IHC staining for Ki67 (MIB-1, DAKO) was performed automatically using an IHC machine (BenchMark® XT, Ventana Medical Systems, Inc.). The Ki67 labelling index (percentage of positivity) was calculated for approximately 500 cancer cells in hot to warm areas.
Pathological complete response (pCR) to NAC was evaluated in accordance with the guidelines of the Japanese Breast Cancer Society. The details of this evaluation are described elsewhere39 (link). Residual noninvasive cancers or axillary lymph node metastases were not considered while determining the pCR.
Pathological complete response (pCR) to NAC was evaluated in accordance with the guidelines of the Japanese Breast Cancer Society. The details of this evaluation are described elsewhere39 (link). Residual noninvasive cancers or axillary lymph node metastases were not considered while determining the pCR.
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