[Histonet] pERK staining in PFA Fixed tissues

[Mehlika Faire]

Hello all,
I am a Master's student working on staining for pERK in 4% PFA fixed tissues.  I came across several protocols where researchers fixed their slides/tissues in PFA and treated their slides/tissues with a methanol gradient (50% to 100% ;dehydration), followed by a ethanol gradient(100% to aqueous).  I know people have done this for paraffin fixed tissues, but I am not sure why it is necessary for PFA fixed tissues.  Does anyone know the principle behind these steps for pERK staining? Or anyone have a reliable protocol of pERK in PFA fixed sections?
Thank you in advance
Mehlika