degraded cDNA from immunohistochemically stained tissues - degraded cDNA from immunohistochemically stained tissues (Feb/06/2002 )
RNA isolation from immunohistochemically stained frozen tissues with subsequent RT-PCR works well.
However, after freezing of cDNA the PCR doesn`t work anymore.
There is no cDNA detection anymore.
cDNA is quite stable at -20 -80 degrees for at least six months. find out if they has been any change in your PCR reagents especially the Taq making sure it stillhas its properties. Also continues thaw and freeze cycles of the cDNA could lead to degredation