Tissue Microarrays: A Modernization of the Bio-Specimen Industry

Tissue Microarrays: A Modernization of the Bio-Specimen Industry

Background

Tissue Microarrays (TMA) are one of the premier methods of organizing specimens to facilitate diagnostic research. The TMA method, introduced by H. Battifora in 1986, is used extensively in the field of histology. (1) The creation of a tissue microarray serves as an avenue to analyze multiple specimens at the same time. (2)

One microarray or “tissue chip” contains many small representative tissue samples organized into one histological slide. A tissue microarray is comprised of a paraffin block produced by extracting cylindrical tissue cores from different paraffin donor blocks and re-embedding these into a singular block. A paraffin block can be housed at room temperature for years and hold up to 1000 tissue samples. (2)

TMA Applications 

Tissue biopsies are a staple in the medical field for both diagnostic and research purposes. Traditional tissue sample methods require a healthy amount of tissue and the process is both labor-intensive and time-consuming. From a pathological standpoint, TMA slides are a game-changer. The old way involved creating a new slide for each potential genetic marker for each individual patient or donor. (3)

With TMA, a whole slide approach can now be screened for several different biomarkers from the same patient – a complete thorough process towards understanding mechanisms of action. This is where using a quality biorepository is an integral part of major research objectives. Medical professionals have at their fingertips the ability to order customized tissue microarray samples. (5) Those samples can then be utilized in the scope of various analytical methodologies such as: 

  • IHC (Immunohistochemistry): The preferred analytical method for in-situ (place of origin) protein expressions in tissue samples. 

  • RNA: A popular technique that uses RNA sequencing for transcriptional profiling, editing, and analyzing gene expression. 

  • FISH (Fluorescence in situ hybridization): A technique that uses fluorescent probes that bind only to those parts of a nucleic acid sequence with a high degree of sequence complementarity. 

TMA Variations 

Tissue procurement is a scientific art form that has zero room for mistakes or interpretation. A quality biorepository will be able to process tissue specimens for a multitude of uses and analytical methods. SOP comes into strong play alongside integrity for the practice itself – biorepositories is a foundational element for all research activities. (6) The following are variations commonly used:

Formalin-Fixed Paraffin-Embedded Tissues (FFPE)

A tissue of preservation for biological specimens that aid in the examination and experimental research, and diagnostic development. Formalin is a formaldehyde derivative that helps preserve vital proteins and structural components within the tissue sample.

Frozen Samples

Frozen or Cryosection samples are often used in the context of oncological surgery as opposed to research. Although they are primarily used for rapid diagnostic contexts, frozen samples are used to view cell morphology, structure, and biochemistry disease, and mechanisms of action. The applications, pros, and cons are easily distinguished in laboratory science. 

Customizations

The chief benefit of working with Geneticist is that we tailor TMA samples unique to our clients. This helps scientists more efficiently analyze gene and protein expressions.

Why Do IRB Compliant TMA and FFPE Samples Matter? 

There are three types of research concerning specimens. Each type is governed by strict regulatory standards and federal mandates. The rules are in place to ensure specimen collection meets the ethical and safety standards set by many various governing bodies. The role of biorepositories crosses all regulatory frameworks and therefore requires the highest adherence level. The aspects that pertain to each are varied, but similar in the fact research activities and methods are subject to intense scrutiny throughout the following submission applications: drug discovery, new drug submissions, clinical trials, and modifications. (7) 

Failure to meet these standards can halt or slow the approval of anyone these processes resulting in significant losses of time and money. Hence; the importance of providing IRB compliant tissue specimens is the benefit of ordering samples from a biorepository with an excellent track record and relevant partnerships with research sponsors who are also held in high esteem. 

Research Specimen Types

  • Prospective Sampling: Samples have been approved through an IRB approved protocol for non-research purposes. 

  • Specimen Repositories: Tissue banks that have data associated with them i.e. demographic, behavioral.

The Role of IRB and Biorepositories

Biorepositories house thousands of specimens and samples of various kinds and they are required to have an approved IRB plan in place. The FDA and other regulatory agencies such as HIPAA, and  OPHS also maintain active involvement and rules of operation for tissue banking facilities. These regulating interventions are in place to oversee the collection, storage, and distribution of all the samples. (8)

Geneticist maintains all regulatory standards and our specimens and methodologies meet every compliance benchmarks. We also ensure the strictest controls and optimal storage solutions for all samples including biologics, blood serums, tissues, and other bio-components for the use of analytical research.

References:

1. [Online] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3599403/.

2. [Online] https://www.ncbi.nlm.nih.gov/pubmed/3525985.

3. [Online] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813639/.

4. [Online] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2813639/.

5. [Online] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3599403/.

6. [Online] chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/https://publications.iarc.fr/_publications/media/download/1398/68b153f74693289ae66d767a8cbe1ca667df4f1b.pdf.

7. [Online] chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/https://www.unthsc.edu/research/wp-content/uploads/sites/21/Guidance_on_Research_Using_Human_Biological_Materials__Samples_.pdf.

8. [Online] https://www.ncbi.nlm.nih.gov/books/NBK493627/.

9. [Online] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3599403/.