ROBO1 and central nervous system cancer: Slit2 mediates directional migration of glioma cells [73] and its expression is elevated in human colorectal carcinoma tissues and cell lines [71] and Robo1 was found upregulated in colorectal carcinoma tissues, suggesting the possibility of an autocrine mechanism through which colorectal carcinoma cells secrete Slit2 for signaling through Robo1 expressed on these same cells.