Analysis of the tumor-associated WN-Fc fusion proteins by fluorescence microscopy

Around two weeks after tumor cell inoculation, rhodamine conjugated WN-Fc fusion proteins were injected intravenously into separate animals using 200 μg of the conjugate in 100 μl of physiological saline. Mice were sacrificed 18 h after injection and tumors and other organs (lungs, kidneys and heart) were removed and incubated overnight in 4% paraformaldehyde solution and then embedded in optimal cutting temperature medium (OCT). Tissue sections were incubated with Hoechst 33342 for nuclei staining. Thereafter, the slides were covered with Dako cytomation fluorescent mounting medium before examination under an epifluorescence microscope (Leica DM RHC, Leica Microscopy As, Oslo).