All these suggest Slug protein could be SUMOylated under different regulation and affected cancer malignancy with different action mechanisms; while ARF overexpression, Slug was SUMOylated at K192 to accumulate Slug protein to promote prostate tumorigenesis in vivo; when hypoxia or Ubc9/PIASs overexpression, Slug was SUMOylated and enhanced transcriptional repression activity in lung cancer malignancy. The gene discussed is UBE2I; the disease is lung cancer.