Prior to deciphering the mechanism underlying IFN-γ-induced cancer metastasis, we first verified the pro-metastatic effect of IFN-γ in five cell lines of different human cancers (Figure 1A): the kidney cancer cell line Caki-1, the lung cancer cell line A549, the cervical carcinoma cell line CaSki, the breast cancer cell line BT549, and the colon cancer cell line HCT116. Here, IFNG is linked to cancer.