The mechanism whereby CKAP4 enhances the inhibitory effect of APF on bladder cancer cell proliferation involves upregulation of tumor suppressor gene p53 expression, along with the activation of AKT/GSK3β/β-catenin phosphorylation and downregulation of MMP2 expression (Shahjee et al., 2010) (Figure 2). Here, CKAP4 is linked to urinary bladder carcinoma.