Five large families of canonical guidance proteins have been identified: netrins that signal through the deleted in colorectal cancer (DCC), Neogenin and UNC-5 receptors; Slits, that bind to their roundabout (Robo) receptors; Semaphorins, that activate both Neuropilin and Plexin receptors; Ephrins and Ephs; and Repulsive Guidance Molecule family (RGMs) that bind to Neogenin. The gene discussed is NEO1; the disease is colorectal cancer.