PTK2 and colorectal carcinoma: To investigate whether GRB7 confers resistance to MEKi by mediating the RTK pathway, we characterized the activation status of effectors within this pathway, including FAK, STAT3, AKT, mTOR, 4EBP1, and ERK in CRC cell lines with or without GRB7 knockdown in the presence of MEK inhibitors (Fig. 4A and Supplementary Fig. S4F).