Multicolour immunofluorescence on tissue sections is very informative, when it comes to the expression of various tissue and differentiation markers. However, usually it is performed in cryostat sections: the cell and tissue morphology has to be sacrificed to preserve the antibody reactivity.
And quite often, when dealing with small tissue samples, such as biopsies, early stage embryos, unique tumours and other tissue abnormalities from transgenic mice, one would like to have both: fix the material in formalin (with embedding) to preserve the morphology, and to perform IF staining of sections obtained from fixed tissue.
In their recent publication Villasenor et al (2012) had exactly the task described above: they were studying expression of EphB3 in developing pancreas. They fixed the embryos and, using 2100 Retriever, unmasked all the required antigens for double immuno-fluorescence.