ROBO1 and colorectal carcinoma: Further study showed that blocking Cdc42 activity using a dominant negative form of Cdc42 (DNCdc42) could mimic the migration inhibition effect of Slit2, whereas ectopic expression of CACdc42 (constitutively active) could retrieve the decreased cell motility in Slit2-treated CRC cells, suggesting that Cdc42 is a major functional target of Slit2-Robo1-srGAP1 signaling in inhibiting CRC cell migration (Fig. 5c-d).