Nondestructive quality control of HER2 control cell line sections: the use of interferometry for measuring section thickness and implications for HER2 interpretation on breast tissue.

ABSTRACT

The field of companion diagnostics is an expanding area in which industry can make significant contributions to the quality and reliability of prognostic and predictive assays. HER2 testing by immunohistochemistry and in situ hybridization, by virtue of its semi-quantitative nature demands the highest level of reagent quality and consistency. We describe a unique manufacturing practice that is used to guarantee the quality of control cell line slides provided for controlling the staining procedure and ensuring the validity of the reagent performance. An IHC control that could reflect variations in fixation, processing, section thickness, section storage and staining protocols would provide a useful tool for improved standardization. One way to ensure such accuracy and reproducibility of HER2 testing is by using robust internal controls. We intend to present for the first time, details of a unique manufacturing process, that of interferometry, the technique of using the pattern of interference created by the superposition of 2 or more waves to diagnose the properties of the aforementioned waves, that is, "section thickness," to guarantee the quality and consistency of internal cell line controls that can be used in a HER2 testing assay.