GAPDH and colorectal cancer: To determine whether GABABR can inhibit NF‐κB to repress the colorectal cancer cell proliferation, we first performed western blot experiment to find that phosphorylation level of p‐IKBα and p‐NF‐κb‐p65 were downregulated compared with GAPDH,while the whole expression of IKBα and NF‐κb‐p65 were not changed significantly, which mean that the NF‐κB was activated (Fig. 4A).