Moreover, UfSP2 depletion exacerbated ERα-mediated tumor formation; however, the expression of an ASC1-UFMylation-defective mutant or the depletion of UBA5 inhibited tumor growth, suggesting that the UFMylation of ASC1 is important for the transactivation of ERα and thus breast cancer development [17]. This evidence concerns the gene ESR1 and breast cancer.