The procurement, storage, and quality assurance of frozen blood and tissue biospecimens in pathology, biorepository, and biobank settings

Abstract

Well preserved frozen biospecimens are ideal for evaluating the genome, transcriptome, and proteome. While papers reviewing individual aspects of frozen biospecimens are available, we present a current overview of experimental data regarding procurement, storage, and quality assurance that can inform the handling of frozen biospecimens. Frozen biospecimen degradation can be influenced by factors independent of the collection methodology including tissue type, premortem agonal changes, and warm ischemia time during surgery. Rapid stabilization of tissues by snap freezing immediately can mitigate artifactually altered gene expression and, less appreciated, protein phosphorylation profiles. Collection protocols may be adjusted for specific tissue types as cellular ischemia tolerance varies widely. If data is not available for a particular tissue type, a practical goal is snap freezing within 20 minutes. Tolerance for freeze-thaw events is also tissue type dependent. Tissue storage at −80°C can preserve DNA and protein for years but RNA can show degradation at 5 years. For −80°C freezers, aliquots frozen in RNAlater or similar RNA stabilizing solutions is a consideration. It remains unresolved as to whether storage at −150°C provides significant advantages relative to −80°C. Histologic quality assurance of tissue biospecimens is typically performed at the time of surgery but should also be conducted on the aliquot to be distributed because of tissue heterogeneity. Biobanking protocols for blood and its components are highly dependent on intended use and multiple collection tube types may be needed. Additional quality assurance testing should be dictated by the anticipated downstream applications.

A critical analysis of cancer biobank practices in relation to biospecimen quality

“…Once a biospecimen is under the control of a biobank, it is important that collection, processing, storage and shipping occur according to defined, evidence-based protocols which are in place to maximise sample integrity. Considerations regarding the procurement, optimal storage temperatures (including freeze-thaw cycles) and quality control (QC) tools for tissue and blood samples have recently been reviewed in detail elsewhere (Ahmed 2011;Hubel et al 2014;Shabikhani et al 2014). Biophysics research using methods such as confocal Raman spectroscopy (Dong et al 2010) has been critical for increasing our understanding of nucleation and ice crystal growth within cells and tissues, and has thereby provided an evidence base for biospecimen freezing and low-temperature storage protocols (Hubel et al 2014).…”

“…The results of these activities, which include confirming patient identity, histological diagnosis, and percentage of tumour cells, as well as routine database audits (Shabikhani et al 2014), may determine whether samples are retained within the biobank and/or provided to researchers (Herpel et al 2010) (Fig. 3).…”

“…Cancer biospecimens can be used in a variety of experiments requiring DNA, RNA, protein, lipids and other cellular constituents. These cellular components exhibit different stability and robustness (Shabikhani et al 2014). For example, it is widely accepted that DNA is relatively stable, being designed to carry genetic information between generations.…”

Logistic Steps of Tissue Sample Processing in a Clinical Biobank - A Short Overview

“…13 Well preserved tissue biospecimens (frozen as well as formalin-fixed paraffin embedded) that are stored under optimal conditions can preserve DNA, RNA and protein for many years. 6 One of the major tasks in a biobank is sample management. This general term encloses the logistics and documentation during all steps and stages of tissue sample processing from sample collection until final storage.…”

“…Preanalytical activities have a high impact on the quality of the collected samples and subsequently on the results of laboratory testing performed on these specimens. 5,6 Critical factors in the preanalytical phase are cold and warm ischemia time, time intervals between the different stages of sample processing or transport and storage conditions (temperature, duration, or the used protocols: e.g. amount of formaline).…”