ROBO1 and neoplasm: In WT mice, ROBO1-FL-expressing tumour cells displayed a predominant population in liver metastatic niches, especially in Kpc1199Mix-I-modelled cells, during coadaptation with hepatocytes, while in Slit2/CKO mice, Kpc1199CTRL cells outcompeted Kpc1199Robo1-FL cells in the absence of SLIT2 (Fig. 5j, k).