USP18 and lung cancer: The DUB USP18 affects protein stability.21–23 Loss of USP18 expression reduced lung cancer cell-line growth and lung tumor formation after transfectants were tail-vein injected into syngeneic mice.21 To explore comprehensively how USP18 altered the growth of lung cancer cells, engineered USP18 knock-down was achieved independently by shRNAs, respectively, in murine and human lung cancer cell lines versus controls.