Stabilization of Tissue Specimens for Pathological Examination and Biomedical Research

Abstract

Human tissue specimens are critical reagents in the diagnosis of disease and biomedical research. Tissues experience rapid degradation immediately after ligation from their blood supply. A variety of processing techniques are employed to prevent the degradation of tissue samples, principally chemical fixation and thermal processing. The success of processing techniques is measured by the preservation of tissue morphology, as well as the critical biomarkers. In preservation of tissue specimens, formaldehyde is the most widely used fixative that maintains tissue morphology. However, the cross-links resulting from chemical interactions between formaldehyde and biomolecules in the specimens introduce difficulties in detection and extraction of antigens for analysis. Alternative processing methods, such as chemical fixation (e.g., alcohol-based) or thermal processing (e.g., freezing) help avoid the loss of antigenicity due to cross-linking, but introduce morphological artifacts. In this article, we review methods of processing of fresh tissue samples, as well as the effects of these procedures on morphology and antigenicity of the preserved tissues as assessed by histology, immunohistochemistry, proteomics, and genomics.

Feasibility Study for the MALDI‐MSI Analysis of Thyroid Fine Needle Aspiration Biopsies: Evaluating the Morphological and Proteomic Stability Over Time

“…Tissue specimens need to be properly handled to ensure not only the integrity of the morphological structure but also to avoid protein degradation . Several protocols have been developed for this purpose, such as chemical fixation followed by paraffin wax embedding and snap freezing . Heat‐fixation of the tissue is also used, but changes in the fine structures of the cells has been observed .…”

“…Hence, for diagnostic or prognostic purposes, along with predicting response to therapeutic treatment, biological specimens, such as tissues and biopsies, must be properly collected and handled in order to assure the preservation of the morphological structure and the proteomic profile, avoiding degradation or alteration phenomena, contamination, and artifacts formation . So far, several attempts have been aimed at preventing sample degradation . Two of the most commonly used approaches for sample preservation and stabilization in pathology and proteomics are chemical fixation (e.g., formalin followed by paraffin wax embedding) and snap freezing .…”

Preanalytics and Precision Pathology: Pathology Practices to Ensure Molecular Integrity of Cancer Patient Biospecimens for Precision Medicine

“…The issue of unknown specimen quality profoundly affects biomedical research as well as clinical practice. 2,5,8,[16][17][18][53][54][55] Most of the biospecimens that fuel translational research and the correlative science in clinical trials are apportioned from clinical samples acquired for medical purposes, not research. This is true of most tumor samples used for correlative scientific studies in clinical trials and for so-called discard specimens that are ''left over'' following diagnostic evaluation and are then used in discovery research or product development.…”

Introduction: The Cardinal Role of Biobanks and Human Biospecimen Collections in Biomarker Validation: Issues Impeding Impact of Biomarker Research Outcomes

“…This is particularly important for biological fluids but also for tissues especially in the cancer field. [30][31][32][33][34][35][36][37][38] It is essential that the levels of expression of biomarkers that are used to make treatment decisions be accurately attributable to the underlying biology and not due to artifacts. Several authors have identified a variety of issues and barriers that can affect the transfer of clinical tests from research to clinical practice: differences in sample collection, handling or storage.…”