Dewaxing unmounted sections - (Jul/06/2008 )

Hi,

I have been doing DNA extraction from Formalin fixed paraffin embedded tissue sections. I normally receive mounted sections, and thus dewax them while on the slides and scrape the remaining tissue. The latest batch of samples I collected however have not been mounted and are a scroll of paraffin embedded tissue. I am worried that I will not be able to separate the xylene and the tissue.

I was wondering if anyone knows (or has a protocol) how to dewax these samples without losing the tissue.

Can I simply add xylene and alcohols to the samples, leave then for the desired times, then centrifuge the sample and remove the solutions as a supernatant?

I would appreciate any help I can get.
Thanks,
Brett

+ xylene
vortex 10''
centrifuge 10000g RT 5'
repeat

+ etoh 100%
vortex 10"
centrifuge 10000g RT 5'
repeat 2x

(do you always use a Proteinase K step after dewaxing?)

Hi minim,

Thanks for the reply, I thought it should be a fairly easy process but wanted to check before wasting some precious sample.

As for the proteinase K step you asked about, I am currently using a solution which claims to be able to isolate DNA from FFPE tissue without the need to do anything else, including dewaxing. i.e. add the solution and heat. I find however the remaining paraffin interferes with the analyses of DNA quality when using the nanodrop so I have been dewaxing the samples first, then using this solution. At present this appears to be working, although I am yet to fully test the downstream processes.

Do you recommend a Proteinsase K step?

Also if you would like to try out the reagent I mentioned I will be happy to provide the details, just not sure what the rules are mentioning brand names in the forum.

All the best,

Great link,
Thanks.