Test Catalog

Test ID: HERDN    
HER2, Breast, DCIS, Quantitative Immunohistochemistry, Manual No Reflex

Useful For Suggests clinical disorders or settings where the test may be helpful

Determining overexpression of HER2 protein on formalin-fixed, paraffin-embedded tissue sections in ductal carcinoma in situ or solid/intracystic papillary carcinoma breast tissue


This FDA-approved test is most frequently used to evaluate HER2 overexpression in breast cancer

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

The HER2 (official gene name ERBB2) proto-oncogene encodes a membrane receptor with tyrosine kinase activity and homology to the epidermal growth factor receptor.


Amplification and overexpression of the HER2 gene in human breast, endometrial, ovarian, and other epithelial cancers have been associated with a shorter disease-free interval and shorter overall survival. Overexpression of HER2 protein is an indication for Herceptin therapy in patients with breast cancer.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Reported as negative (0, 1+), equivocal (2+), and strongly positive (3+) according to the interpretation guidelines for the FDA-approved Ventana Pathway HER2 (4B5) antibody.

Interpretation Provides information to assist in interpretation of the test results

Results are reported as negative (0, 1+), equivocal (2+), and strongly positive (3+) according to the interpretation guidelines for the FDA-approved Ventana Pathway HER2 (4B5) antibody.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The performance and quality of immunohistochemical stains in formalin-fixed, paraffin-embedded tissue depends critically on proper fixation.


Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Riber-Hansen R, Vainer B, Steiniche T: Digital image analysis: a review of reproducibility, stability and basic requirements for optimal results. Apmis 2012 April;120(4):276-289

2. Gavrielides MA, Gallas BD, Lenz P, et al: Observer variability in the interpretation of HER2/neu immunohistochemical expression with unaided and computer-aided digital microscopy. Arch Pathol Lab Med Feb;135(2):233-242

3. Cuadros M, Villegas R: Systematic review of HER2 breast cancer testing. Appl Immunohistochem Mol Morphol Jan 2009;17(1):1-7

4. Nassar A, Cohen C, Agersborg SS, et al: Trainable immunohistochemical HER2/neu image analysis: a multisite performance study using 260 breast tissue specimens. Arch Pathol Lab Med 2011 July;135(7):896-902