Abstract: Objective To study the expression levels of leptin receptor（LEPR） in breast cancer cell lines, normal breast samples and malignant breast cancer samples, and to analyze the expression correlation between LEPR and estrogen receptor（ER）, E-cadherin（E-Cad）, c-Myc and cyclin D1 in order to provide mechanism clues for obesiety associated breast cancer. Methods Using RT-PCR and Western blotting, we examined the expression of LEPR in different breast cancer cell lines. The expression level of LEPR was analyzed by RT-PCR in 5 paired breast samples. In the meanwhile, The expression of LEPR, ER, E-Cad, c-Myc and cyclin D1 was analyzed using realtime PCR in 45 breast cancer samples and 15 normal breast samples. The correlation was analyzed between the expression of LEPR and the expression of ER, E-Cad, c-Myc and cyclin D1 using SPSS statistic software. Results LEPR mRNA and protein were expressed in all breast cancer cell lines tested in this study. The expression of LEPR in the breast cancer samples was higher than in the paired adjacent normal breast tissues. With the statistic analysis, the expression of LEPR was correlated with expression of ER in both normal and malignant breast samples. LEPR expression was also close correlated with E-Cad and c-Myc expression in the breast cancer samples, but not with cyclin D1 expression. Conclusion LEPR expresses in breast cancer cell lines. Compared to the normal breast tissues, the expression of LEPR in breast c

Key words: Leptin receptor, Breast cancer, RT-PCR, Western blotting, Human