Quality Control of Immunohistochemical and in Situ Hybridization Predictive Biomarkers for Patient Treatment: Experience from International Guidelines and International Quality Control Schemes

With the advent of routine predictive biomarking of cancers using immunohistochemistry and in situ hybridization, it has become essential to manage the assays involved with the highest standards of quality assurance at the internal and external quality control levels. This is to ensure the reproducibility and accuracy of generating, interpreting, and reporting what are classified as stand-alone Class III category results. To satisfy this need, it is required to use approved validated and standardized tests applied with suitable on-slide or batch controls to engender adequate internal control-based quality assurance. In addition, it is necessary for the laboratory to participate in external quality assurance schemes to align the performance of the assay and the quality of the assay results with regional, national, and international standards on a regular basis. The chapter is written to provide generic information for the reader on the principles and methodology involved for validation of predictive biomarker assays and the critical issues involved in their regular internal and external quality assurance from a perspective of applying these assays at the level of routine diagnostic laboratories as well as at centers of excellence dealing with the screening and reporting of the results of ongoing clinical trials.