Formalin-Fixed Paraffin-Embedded tissue (FFPE) are tissue samples that have been biopsied and prepared for preservation. Formalin is a formaldehyde solution, used for its preservative effects. Paraffin is injected into the tissue sample after the formaldehyde is applied. Paraffin helps to support the tissue sample and protect it from oxidation. FFPE tissue samples help analyze, study, and diagnosing various diseases Additionally, FFPE aids scientists in processing gene expression profiling.

Standard Protocol for FFPE Tissue

There is a specific protocol that must be followed to convert regular tissue samples into regular FFPE tissue slides. Here, we will outline the steps to provide you a greater understanding of our process

Fixation

Fixation is the first step in gathering FFPE tissue slide. Technicians must utilize the correct solution of formalin and paraffin-based on the thickness. The thickness of the tissue sample will determine the quality of the fixed sample. Thicker samples will require more products and more time to reach the center of the tissue.

Dehydration

Paraffin is immiscible with water, so all the water from the formalin solution must be removed from the tissue slide completely. This is done by applying 70% alcohol and slowly increasing to 100% alcohol. Insufficient dehydration of the FFPE tissue sample can lead to tissue degradation, which can harm the process of research and diagnosis.

Clearing

This step involves removing the alcohol from the tissue slide with a solution that is miscible with paraffin. Xylene is the most common clearing agent utilized in this step.

Paraffin Infiltration and Embedding

This step of the process is not standardized, however, our FFPE tissue specimens are collected under IRB approval and conducted by certified medical pathologists. The tissue sample is injected with and surrounded by paraffin. When our technicians conduct FFPE sampling, they fix the tissue in 10% Neutral-Buffered Formalin (NBF) within 30 minutes of surgical excision. Then, the tissue is fixed for 18-24 hours at room temperature, before being embedded in IHC-grade paraffin. Once the paraffin casing has solidified, the FFPE block is ready to be preserved in storage at room temperature. The fixation agent can be customized upon request, and unless indicated otherwise, all FFPE tumor tissue contains at least 50% tumor content.

Application of FFPE Tissue

Double-stranded DNA is incredibly stable in FFPE blocks, but less stable molecules such as RNA may degrade within a decade. FFPE is useful because it’s incredibly resilient and can be used for research almost indefinitely, as long as it is stored properly and conducted by a certified and trained professional. FFPE tissue samples include antibodies that bind to specific proteins or structures, allowing doctors to easily identify signs of disease such as cancer or Alzheimer’s.

Alzheimer’s.

Oncology: FFPE tissue slides are critical to the study of oncology. Preserved tumor tissue showcase characteristic morphologies and specific proteins that are used in diagnosis.
Hematology: FFPE tissues is critical when studying blood-related disorders. Hematology has helped scientists and doctors discover cures for numerous diseases caused by abnormalities in the blood.
Immunology: Studying tissue samples from a person with an autoimmune disease, such as Lupus or Celiac disease, allows scientists to understand the cause of the disease. Once the cause of the disease is identified, they can create a medication or treatment for that disease.
Comparative Research: Tissue from healthy donors is imperative for research. Researchers can compare diseased or unhealthy tissue with healthy tissue, which is critical for the development of new treatments and the future of medicine.

Explore our FFPE tissue blocks inventory in our biorepository.

What’s the Difference Between FFPE Tissue and Frozen Tissue?

While we provide frozen tissue services, FFPE has a few advantages that frozen tissue does not provide. However, frozen tissue still provides advantages and benefits in some situations. Speak with a professional to identify which test would be best for you.

Storage: FFPE tissue slides can be stored and studied for years, and require more cost-effective methods. Frozen tissue requires expensive freezers that require energy and maintenance.
Durability: Due to their fragility, frozen tissues can be difficult to preserve long-term. The tissue deteriorates at a faster rate than FFPE tissue. Frozen tissue degrades quickly while in room temperature environments.
Uses: Tissue samples that require staining and morphology study, FFPE tissue samples are most beneficial because they can be handled in various studies.

A primary disadvantage of frozen tissues is that they are not allowed to thaw after initial freezing, however, they work very well for molecular genetic analysis. Learn more about our frozen tissue sampling services.

Sources:

https://lab-ally.com/histopathology-resources/ffpe-samples/
https://www.biochain.com/general/ffpe-vs-frozen-tissue-samples/
https://www.biochain.com/general/what-is-ffpe-tissue/