In article <[email protected]>, [email protected] says... > > On 16 April 2013 13:13, Shahrzad Jalali <[email protected]> wrote: > > > Isolation of RNA from formalin fixed paraffin tissue is doable. I have done > > it. Use High Pure RNA paraffin Kit from Roche..... > > > > Would you be able to share some of the details and experiences. My cells > are not in paraffin, so I can exclude the Xylene steps. However, I am > concerned about the formaldehyde crosslinks...!
Although methanal (formaldehyde) is a cross-linking fixative, the number of cross-links introduced per macromolecule is small, especially if the exposure time is short. FFPE material was usually exposed only for a few hours to a day, whilst material stored in formalin for years may be more of a problem. Techniques that use only a relatively small section of a macromolecule will still work on FFPE samples. My personal experience is with antibody binding: polyclonal serums are rarely a problem. With monoclonals the chance is at least fair, although there are monoclonals that are known not to work on FFPE sections. Where I would be more cautious is with quantitative measurements, the extraction efficiency will invariably be lower than with fresh material, and may depend on the exact condition that each sample was exposed to (in particular, exposure time). The solution can sometimes be micro- dissection where both the experimental and control tissue come from the same block. In such cases, paired tests may give you valid results. -- Car (noun): erratically moving obstacle on the road _______________________________________________ Methods mailing list [email protected] http://www.bio.net/biomail/listinfo/methods
