This is in line with previous literature that suggests proliferation measured by Ki67 is a good prognostic factor in patients with CRC.25,26 However, if only ERK phosphorylation is high, then the hyperactivation in BRAF mutant tumours will be uncontrolled and start to suppress the cell cycle, leading to decreased proliferation and reduced patient survival. This evidence concerns the gene BRAF and colorectal carcinoma.