Pre-analytic variables and phospho-specific antibodies: The Achilles heel of immunohistochemistry

Abstract

Immunohistochemistry is the most common method for companion diagnostic testing in breast cancer. The readings for estrogen receptor, progesterone receptor, and Her2 directly aff ect prescription of critical therapies. However, immunohistochemistry is highly sensitive to innumerable pre-analytic variables that result in loss of signal in these assays. Perhaps the most signifi cant pre-analytic variable is cold ischemic time. The work of Pinhel and colleagues in the previous issue of Breast Cancer Research examines the eff ects of cold ischemic time and fi nds a chilling result. The authors show that while the classic markers may be only mildly aff ected, phospho-specifi c markers are highly sensitive to this artifact. As a result, it is likely that future companion diagnostic tests that include phosphospecifi c epitopes will be reliably done only in core needle biopsies that minimize ischemic time.© 2010 BioMed Central Ltd.