UBE2I and endometrial cancer: For endometrial cancers of different differentiation levels (stages I, II, and III), the expression of SUMO1, SUMO2/3, UBC9, SENP1, and SENP5 is significantly higher than that of normal tissues, except for SUMO1 in stage I and SENP1 in stage II, which show no significant changes compared to the normal group UBC9 (Figure 2B).