FLT1 and colorectal carcinoma: Although it is widely accepted that the blockade of VEGFA/VEGFR2 is crucial for inhibiting neovessel formation, mainly for the direct effects on endothelial cells, the impressive anti-tumor activity achieved with the irinotecan-iVR1 combination in CRC models, and the resulting outstanding survival rate comparable to that of irinotecan-bevacizumab combination, strengthen the concept that a potent and selective VEGFR1 inhibition produces therapeutic effects comparable to those caused by the blockade of VEGF-A.