During embryonic development cells communicate with each other and respond to environmental signals in order to evolve and organize into highly specialized structures such as tissues or organs. These cues are integrated by the cells and influence processes such as fate determination, migration or proliferation. In several human diseases such as cancer these same signals are defective. Using cutting-edge proteomic, cell biological and biochemical tools we are investigating how the Wnt family of proteins, which constitute one of the most important of these signals, are integrated by signalling pathways inside the cells and how they are defective in cancer.