STAT3 and colorectal carcinoma: Additional indirect evidence that STAT3 mediates resistance to CRT comes from studies by Urick and colleagues, who treated CRC cell lines with the MEK inhibitor, selumetinib, which resulted in increased sensitivity to 5-FU-based CRT in vitro and in vivo, with DMFs at 10% survival rate of 1.52 and 1.78, respectively [63].