A couple of years ago I did some FLT1 stainings on FFPE mouse xenografts of human tumor cells. We were also having difficulties to believe the staining as it was mainly localized to the nucleus. My solution was to use the same human tumor cells in tissue culture, separate the nuclear and cytoplasmic proteins and run a Western. This showed that the signal from the nucleus was specific. Similar findings for EGFR has been reported by others:
Lo HW, Ali-Seyed M, Wu Y, Bartholomeusz G, Hsu SC, Hung MC. Nuclear-cytoplasmic transport of EGFR involves receptor endocytosis, importin beta1 and CRM1. J Cell Biochem. 2006 Mar 21.
I don't know if this will help your interpretation, but it might be good to have in mind.
From: Cathy Malcontenti-Wilson
Sent: torsdag, april 24, 2008 03:05
Subject: [Histonet] VEGF R1/Flt-1 Immunostaining on FFPE mouse tissues
I would very much appreciate some help from someone who is doing/has
done some immunostaining of FFPE mouse tissues with an antibody against
VEGF Receptor 1/Flt-1. We are currently having difficulties believing
the staining we are getting with the protocols we have tried.
The antibody we have is Santa Cruz Flt-1 c-17 (sc-316).
I would be grateful for any help.
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