ABSTRACT
In the modern era of precision medicine, a number of class II immunohistochemistry (IHC) biomarkers are routinely tested in pathologic laboratories to select cancer patients who may be candidates for hormonal, targeted, and immune therapies. Pre-analytical factors, including tissue processing, are critical components of biomarker testing and require validation to ensure reliable results. In this study, we aimed to study the impact of tissue processing on biomarkers (including ER, PR, HER2, mismatch repair (MMR) proteins, BRAF V600E, and PD-L1) in a large prospective cohort of 109 tumors. We found that ER and MMR were not impacted; PR, HER2, and BRAF V600E were minimally affected; and PD-L1 regardless of the antibody clone was strongly influenced by a combination of tissue processing procedures and intratumoral heterogeneity. Our findings suggest that validation of pre-analytical parameters, such as tissue processing, is important for certain class II biomarkers, in particular PD-L1 IHC.
Subject(s)
Biomarkers, Tumor/analysis , Immunohistochemistry , Neoplasms/chemistry , Tissue Preservation , B7-H1 Antigen/analysis , Biomarkers, Tumor/genetics , Biopsy , DNA Mismatch Repair , DNA Repair Enzymes/analysis , Humans , Neoplasms/genetics , Neoplasms/pathology , Predictive Value of Tests , Prospective Studies , Proto-Oncogene Proteins B-raf/analysis , Proto-Oncogene Proteins B-raf/genetics , Receptor, ErbB-2/analysis , Receptors, Estrogen/analysis , Receptors, Progesterone/analysis , Reproducibility of ResultsABSTRACT
Tissue contaminants in anatomical pathology are not uncommon. While issues related to the presence of extraneous tissue on glass slides are often easily resolved, this is not always the case and several factors may contribute to diagnostic difficulty. Because of this, familiarity with the different steps involved in handling specimens in the anatomical pathology laboratory is essential when troubleshooting possible cross-contaminants. Most commonly, the specimen constituting the source of cross-contamination is handled before the actual contaminated case; however, this is not always so. In this article, we review the steps involved in processing pathology specimens as they pertain to cross-contamination; share an approach covering how to troubleshoot and prevent tissue contaminants in a systematic and practical manner; present some examples from our own experiences; and compare our experience to what is reported in the literature. The information included in this article will be of use to all members of the anatomical pathology team including medical laboratory technologists, laboratory managers and supervisors, pathologist assistants, trainees in pathology, and pathologists.
