HER2, Gastric/Esophageal, Semi-Quantitative Immunohistochemistry, Manual
Determining overexpression of HER2 protein of gastric and esophageal adenocarcinoma in formalin-fixed, paraffin-embedded tissue sections
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
Cases that are equivocal (2+) by immunohistochemical stain will reflex to HER2 FISH at an additional charge.
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 have been associated with a shorter disease-free survival and shorter overall survival in gastric and gastroesophageal junction cancers, as well as breast, endometrial, and ovarian cancer.(1,2)
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 positive (3+)
Results are reported as positive (3+ HER2 protein expression), equivocal (2+), or negative (0 or 1+).
Equivocal (2+) cases will automatically reflex to H2GEF / HER2 Amplification Associated with Gastroesophageal Cancer, FISH, Tissue at an additional charge.
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 10% neutral buffered formalin-fixed, paraffin-embedded tissue depends on proper fixation. It is recommended (not required) for surgical specimens to be fixed between 18 and 24 hours and biopsy specimens between 6 and 8 hours.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Pergam M, Slamon D: Biological rationale for HER2/neu (c-erbB2) as a target for monoclonal therapy. Semin Oncol 2000;27(5):13-19
2. Gravalos C, Jimeno A: HER2 in gastric cancer: a new prognostic factor and a novel therapeutic target. Ann Oncol 2008 Sep;19(9):1523-1529
3. Meza-Junco J, Au HJ, Sawyer MB: Transtuzumab for gastric cancer. Expert Opin Biol Ther 2009;9(12):1543-1551