The results demonstrated that ROBO1-FL-expressing tumour cells showed increased proliferation and colony formation ability in the presence of recombinant SLIT2 (rSLIT2), and this advantage could be abolished by sROBO, a soluble peptide containing the first 2 Ig domains as a ligand-binding trap (Supplementary Fig. 5c–h). Here, ROBO1 is linked to neoplasm.