Arf6 activation has been shown to be important for cancer cell proliferation, invasion, and metastasis in various cancers, with inhibition of Arf6 suppressing invasion and metastasis.33, 34 This may help explain our findings that plasma levels of CNK3/IPCEF1 are higher in stage III CRC patients with poor outcome. The gene discussed is IPCEF1; the disease is colorectal carcinoma.