Slit protein binds to the roundabout receptor and acts as a midline repellent to guide axonal development during embryogenesis (Rajagopalan et al, 2000; Simpson et al, 2000; Wong et al, 2001) In humans, three SLIT orthologues have been identified, but to date only SLIT2 has been implicated in cancer. Here, SLIT2 is linked to cancer.