USP22 and cancer: USP22 is also considered a marker of metastasis, it induces autophagy and promotes the survival of cancer cells especially in pancreatic cancer (Liu et al., 2011; Yang et al., 2011; Zhang et al., 2011; Ning et al., 2012) enhancing cell proliferation and resistance to chemotherapy under special conditions such as nutrient deprivation or hypoxia.