Deparaffinization, tissue incubation over night in 85 % ethanol - (Jun/28/2013 )

Hi all!

I have a question about the deparaffinization procedure of FFPE tissue. Our lab assistant did the deparaffinization as followed:
- Paraffin melting in the oven (55 ˚C)
- Addition of Xylene, removal of Xylene/ paraffin
- Incubation in Xylene for 30 min
- Incubation in 100 % Ethanol for 30 min
- Incubation in 100 % Ethanol for 30 min
- Incubation in 95 % Ethanol for 30 min

Then, he added 85 % Ethanol and forgot the samples so that they were sitting in 85 % Ethanol overnight at room temperature.
So, what do you think, is the tissue still usable or should I start over again? My aim is not to do histological staining but to extract proteins from the tissue.

Thanks for your help!

Steffi

The proteins will be extensively crosslinked by the fixation and ethanol should preserve this quite well. I don't think there will be any problems.