Introduction to Human Tissue Specimens
Modern research has progressed in many areas such as medical specialties like cancer and lung disease that has required researchers to access high quality specimens such as bodily fluids, tissues, and more. There are now many organizations that have started to collect, process, store and distribute human tissues to help researchers and investigators in the field of biomedical research. Guidelines have been developed as well but mostly constitutes general protocols and do not always include the specific details and knowledge required by investigators who are new to the field of utilizing human tissue in research.
Models of Tissue Collection
To obtain human tissues and bodily fluids as suitable specimens that can be used in research, there are several approaches available.
a) The “Catch as Catch Can” Method
This is one of the more disorganized methods where professionals such as surgeons, pathologists and other healthcare personnel provide their specimens that are available to biomedical researchers. These specimens are often only collected opportunistically when they have a specimen available, if time permits, and if the request is remembered. Generally, these specimens have no quality assurance to how they are collected, processed, and stored which lowers the quality of the specimens. Some experts are also worried about violating the Health Insurance Portability and Accountability Act (HIPAA) regulations or the Institutional Review Board (IRB) requirements.
b) The “Banking Model”
One method that is more organized is to obtain specimens from an organization that has a a standard operating procedure (SOP) is used to collect, process, and store the specimens. These tissues are usually collected and stored as frozen specimens or formalin fixed paraffin embedded (FFPE) blocks. One of the major disadvantages of this method is that specimens might not be able to meet investigator needs when there are specifications such as size, percentage of tumor, or needing fresh tissue. However, the banking model is advantageous as it can provide large number of specimens if it is needed immediately. It may also include important information such as demographics, clinical information, and clinical outcome.
c) The “Clinical Trial Model”
This method is a subset of the banking morel where n organization keeps the remnants of specimens that have been collected from multiple clinical trials. The issues associated with this method are:
- The original consent does not allow the specimen to be used for other purposes.
- The organization’s IRB limits the utilization of specimens for different types of research.
- The remnants collected may be limited in terms of size and number.
- The remnants collected may have been processed and differ from the methods necessary in other studies.
d) The “Prospective Collection Model”
This is a much more specific method where researchers specify the type of specimens needed and how they prefer to have it collected, processed, and stored. This is also the model the Cooperative Human Tissue Network (CHTN) utilizes. The disadvantage of this model is the unavailability of large numbers of specimens and outcome data. The obvious advantage would be that the specimens are collected just how the research team has requested.
e) The “Tissue Repository Model”
This model is a combination of the banking and prospective model and thus, includes the advantages of both models. The term “repository” is used to define an entity that “collects, stores, process, and / or mete out tissue samples” as required. The main disadvantage of this method is that there are more administrative needs and requirements for a more specific and specialized bioinformatics system.
Since there are more organizations that are now developing repositories, an international organization known as the International Society of Biological and Environmental Repositories (ISBER) has been formed to help organizations with their repositories. ISBER has also published guidelines for these biological repositories. Guidelines for repositories that are focused on neoplastic diseases have also been established by the National Cancer Institute (NCI). Details for specific operations are available in both documents.
Variables of Tissue Repositories
Some of the variables of tissue repositories are:
a) Types of tissue – Some repositories may provide only FFPE blocks while some have more variety such as fresh, fixed, or frozen specimens. There are also some repositories that only provide specimens to only one disease such as breast cancer while some have specimens with a wide range of diseases.
b) Population – Since specimens are collected from local medical institutions, the repository has to estimate the types of tissue they will be needing. In situations where a research may need specific specimens collected from a designated population, special arrangements will be needed to obtain specimens from the required population.
c) Services – The services of tissue repositories can greatly affect the resources as not all provide delivery of tissues, extraction of DNA or RNA, culturing cells, and performing extensive analysis on specimens. Providing too many services can take a toll on the organization.
d) Other variables – There are many other variables that can affect tissue repositories such as: the labeling of specimens; collection variables and limitations; time between collection and processing of specimens; storage of specimens; and records of how the specimens were collected, processed, and stored.
1) Grizzle WE, Bell WC, Sexton KC. Issues in collecting, processing and storing human tissues and associated information to support biomedical research. Cancer Biomark. 2010; 9(1-6): 531-549.
2) Frozen human tissues and blood. Tissue for Research. Accessed 4/23/2018. http://tissue4research.com/index.php/formats/frozen-human-tissues-biofluids-biosamples
3) Frozen human tissue for research. Cureline. Accessed 4/23/2018. http://www.cureline.com/frozen-human-tissue-for-research.html