Reproducibility of Equivocal HER2 In Situ Hybridization Groups 3 and 4, and Comparison With HER2 mRNA Expression: The Thin Line Between Amplified and Nonamplified Breast Cancers.

Context.—: Breast carcinomas (BCs) with equivocal HER2 (human epidermal growth factor receptor 2) immunohistochemistry are subjected to in situ hybridization (ISH) to assess HER2 copy numbers. Infrequently, dual-probe ISH also provides equivocal results, designated as ISH groups 2, 3, or 4.

Predictive markers for pathological complete response (pCR) after neo-adjuvant chemotherapy in HER2-positive breast carcinoma.

Objectives: Patients with HER2-positive invasive breast cancer that is node-positive and/or larger than 3 cm are generally treated with neoadjuvant chemotherapy (NAC). We aimed to identify predictive markers for pathological complete response (pCR) after NAC in HER2-positive breast carcinoma.

Methods: Hematoxylin/eosin-stained slides of 43 HER2-positive breast carcinoma biopsies were histopathologically reviewed.