〔Abstract〕 Objective To investigate the correlation between G3 BP1 and endocrine therapy resistance.Methods Gene Expression Omnibus( GEO) database was retrieved to analyze the expression of G3 BP1 mR NA in breast cancer resistant cell lines. 41 specimens of Luminal-like breast tumor were collected and divided into three groups:primary endocrine resistance group,secondary endocrine resistance group and sensitive group. The expression of G3 BP1 protein in each group was analyzed by immunohistochemical staining. Results GEO database showed the expression of G3 BP1 mR NA in endocrine therapy resistant cell lines was higher than that in sensitive cell lines( P<0. 05). The expression of G3 BP1 protein in primary endocrine resistance group was higher than that in secondary endocrine resistance group( 84. 62% vs 30. 00%,P<0. 01) and sensitive group( 84. 62% vs 28. 60%,P<0. 01). Conclusion G3 BP1 is closely related to endocrine therapy resistance in breast cancer. The high expression of G3 BP1 may lead to primary endocrine resistance.