Her2 4b5 rabbit monoclonal antibody

As previously described [17 (link)], we evaluated ER, PR, HER2, and Ki67 expression using the following antibodies, ER (1:100 clone 6F11; Novocastra, Newcastle upon Tyne, UK), PR (clone 16; Novocastra), HER2 (4B5 rabbit monoclonal antibody; Ventana Medical Systems, Tucson, AZ, USA), and Ki-67 (MIB-1; Dako, Glostrup, Denmark). ER- and PR-positive IHC expression was defined according to the modified Allred system: positive, Allred score 3–8 and negative, Allred score 0–2. HER2 status was re-evaluated according to American Society of Clinical Oncology/College of American Pathologists guideline [18 (link)]. HER2 status was considered positive if the score was 3+, and was considered negative with a score of 0 or 1+. Tumors with a score of 2+ underwent FISH or SISH analysis, according to the manufacturer’s instructions (PathVysion kit; Vysis, Downers Grove, IL, USA or HER2 inform; Ventana). Ki-67 expression is presented as the percentage (range 0–100%) of positive tumor cells.
For the molecular subtyping, the following definitions were used: i) Luminal/HER2 negative: ER positive and/or PR positive and HER2 negative; ii) HER2 positive: HER2 positive regardless of ER and PR status; and iii) TNBC: ER negative, PR negative, and HER2 negative.

All cases were reviewed by two experienced gastrointestinal pathologists. For inoperable patients, biopsy specimens were used to evaluate HER2 heterogeneity. All the biopsy specimens were subjected to the analysis if multiple biopsies were performed. For patients with resected specimens, to determine HER2 heterogeneity, all the tumor-containing paraffin blocks were subjected to HER2 assessment.
HER2 staining was performed with an iView DAB Detection Kit (Ventana, Tucson, AZ) on a BenchMark XT automated stainer (Ventana Medical Systems, Inc.,Tucson, AZ) according to the procedures previously described [36 (link)]. HER2 (4B5) rabbit monoclonal antibody (Ventana Medical Systems, Inc., Tucson, AZ) was used.
For HER2 IHC 2+ patients, FISH was performed on a selected section with the strongest HER2 intensity for each case. A Pathvysion HER2 DNA Probe Kit (Abbott Laboratories, Des Plaines, Illinois) was used according to the manufacture`s instructions.