To demonstrate that the effect of C-13 on cells viability is indeed due to a Syk-specific inhibition and not to an off-target interaction, we used Syk-positive CRC cell lines DLD-1, SW620 and HCT-116, and Syk-negative breast cancer cells lines MDAMB231 and BT549 as control. Here, SYK is linked to colorectal carcinoma.