USP18 and lung carcinoma: Several reports implicated enhanced 14-3-3ζ expression in promoting lung cancer metastasis by regulating Par3, TGF-β, or Snail protein expression.28,29,41 ISG15 complex formation regulated expression of a different 14-3-3 family member, 14-3-3σ.41 Gain of USP18 expression opposed ISGl5ylation and stabilized 14-3-3σ expression.41