Paraffin-embedded tissue blocks have been applied in many therapeutic applications and research over the past decades. This is a way to store and make biospecimens for use in research, diagnosis, examination, and therapeutic development. To preserve the tissue sample, it is first fixed with formalin or formaldehyde.
Furthermore, this ensures that vital structures and proteins remain the same as when the tissue is still in the host. It is then embedded in a paraffin wax block to facilitate sectioning and mounting onto microscopic slides for examination. You can also click this website to know how the FFPE tissue blocks are tested.
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Tissues are first taken from healthy and diseased hosts. Oncologists often compare the primary tumor to samples taken from distant metastatic sites in cancer biospecimens. The tissue measured only a few centimeters, depending on the source and tissue. The biospecimen is then immersed in 10% neutral buffered formin for 18-24 hours to harden it.
The tissue is then dried and removed using increasing concentrations of ethanol. It is then embedded in immunohistochemistry-grade paraffin, which is used specifically for embedding formalin-fixed tissues. The time it takes to fix issues is crucial. It can make them unusable for molecular biological studies. It is important to allow for sufficient time for fixation to preserve the tissue.
To preserve quality, samples must be handled with care once they have been obtained. This could include specifications about the tissue purpose, size, and cut off the tissue. A good example is the cutting of muscle along or across the muscle fiber "grain". A certified medical pathologist will assist with sample preparation to ensure accuracy and quality assessment.