中文摘要：

ELF5（E74-like factor 5）也被称为ESE2,属于ETS（E-twenty-six）转录因子家族成员之一,它在调控胚胎发育以及乳腺组织发育中起到重要作用。在桑椹胚时期,ELF5在调控胚胎内细胞团向胚胎形成过程中或是在胎盘发育的细胞命运决定中起到关键作用。在哺乳动物正常乳腺发育中,ELF5可通过诱导细胞定向分化而获得孕期乳腺分泌细胞类型,从而调控乳腺干/祖细胞的命运。在人类乳腺癌中,ELF5是诱导乳腺肿瘤细胞由表达雌激素受体阳性（ER＋）的luminal亚型向表达雌激素受体阴性（ER-）的basal亚型转化的一个关键调控因子,并抑制细胞获得雌激素敏感表型。现主要综述了ELF5的结构特点、功能以及其在哺乳动物乳腺发育中的调控作用。

英文摘要：

E74-1ike factor 5 （ELF5）, also known as ESE2, is a member of the E-twenty-six （ETS） family and plays an important role in regulating the development of embryonic and breast tissues. It has a critical effect on embryonic formation of the inner cell mass or the cell fate determination during embryonic morula. In normal breast development, ELF5 can induce the directional differentiation of the mammary gland stem/pro- genitor cells into mammary gland secretion cell types during pregnancy. However, ELF5 is a key transcrip- tional factor that can not only induce mammary gland tumor cell transformation from the luminal subtypes to basal-like subtypes, but also inhibit cell phenotype towards estrogen sensitivity in breast cancer. Here, the characteristics of the ELF5 transcriptional factor in its structure, biological functions and the effect on the development of mammary gland in mammals are introduced.