Furthermore, inhibition of the SUMOylation of USP39 can enhance the proliferation of cancer cells including breast and hepatocellular cancer via affecting the recruitment of tri-snRNP, suggesting that SUMOylation of USP39 has an essential role in cancer therapy (Wen et al., 2014; Liu H. et al., 2015; Pan et al., 2015) (Table 3). Here, USP39 is linked to cancer.