From my experience, I would recommend DAB for paraffin embedded sections of tumors. Immunoflourescence is indeed sharper and sensitive, thus may give non-specific signals and high background, which could be avoided using DAB-based immunohistochemistry. You may also select antibodies which can be used both in immunoflourescence and immunohistochemistry (available with many companies) for your target protein, and try out with both the methods. After all, there are huge variations in handling techniques and outcomes based on usage as well. Personally, I like DAB based protein localization in "tissues" embedded in paraffin due to the ease of operation, lesser background and also ease of microscopic visualization (simple light microscope can help visualize).

Yes I missed that part altogether. Thanks for pointing out, Dr. Mohamed Mahdy. If your primary antibodies are conjugated with flourochromes, then of course, immunoflourescence.

Thanks for suggestions.