ROBO1 and neoplasm: Tumour cells expressing full-length ROBO1 protein (Kpc1199Robo1-FL or Panc02Robo1-FL) were intrasplenically implanted into Slit2 fl/fl (CTRL), CKO and CKO-RE mice (Fig. 4a; Supplementary Figs. 6b, 7a).