ROBO1 and colorectal cancer: Zelina et al. [40] demonstrated that the key residues required for Slit1−3 binding in the Ig1 domain of Robo1 and Robo2 proteins have been substituted in the mammalian Robo3 receptor and does not bind Slit1−3 with high affinity [38,41]; instead, they form a complex protein with the Netrin-receptor DCC (Deleted in Colorectal Cancer) through their cytoplasm domain [40].