Are the same processing and fixation methods applicable to all cancers?
For IHC !0% formol saline is the usual fixative for most cancers, There are other fixatives which can be used for specific identification of some antigens. But in 95+% of cases formalin is the fixative of choice..
The routine fixative for histotechnique is 4% formaldehyde with phosphatbuffer pH 7,0-7,4 (NBF). I think, not the type of cancer is the point for decision, but the following desired techniques. NBF is good for any morphologic method like H&E and special stains. Also for IHC, FISH and PCR it Is suitable under certain conditions.
It's not suitable for formaldehyde-sensitive enzymes, for PCR of amplicons beyond 200 bp or for Immunfluorescence without any unwanted background.
It is important to get the right informations about the handling of NBF. tissue-size, duration of fixation, speed of penetration, crosslinking, masking of antigens, degradation of nucleic acids, etc.
colon tissue was rapidly dissected and excised, rinsed in saline solution and cut into suitable pieces, then fixed in neutral buffered formalin (10%) for 24 hours, following fixation, the specimens were dehydrated in ascending series of alcohol, then tissue specimens were cleared in xylene and embedded in paraffin at 60 ºC. Section of 5 microns thickness was cut by slidge microtome. The obtained tissue sections were collected on the glass slides and stained by haematoxylin and eosin stain for histopathological examination by the light microscope. for IHC Colon tissue samples were fixed in 10% phosphate-buffered formalin for 10 h at 4°C, dehydrated in ascending concentrations of ethanol, cleared with xylene, and embedded in PolyFin (Triangle BiomedicSciences).
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