Objective To observe the efficacy and side effects of exemestane in postmenopausal breast cancer patients with bone metastasis.Methods One hundred and ten postmenopausal breast cancer patients with bone metastasis were treated with exemestane 25 mg.Results In the evaluable data from 110 patients,the complete remission(CR)was encountered in 7 cases,partial remission(PR)in 28 cases,with a total response rate of 31.8％ ;Thirty nine patients had stabled diseases for more than 24 weeks.It produced a clinical benefit (CR + PR + SD)over 24 weeks in 74 cases(67.3％).Diseases progressed in 12 of the cases(10.9％).The patients with positive ER and PR status had a higher chance to be benefited from the treatment than those with negative receptor status.The clinical efficacy was not correlated with treatment history,pathological subtypes and bone,liver,lung and lymph node metastasis(x2 =0.045,0.078,0.200,P ＞ 0.05).No severe adverse effects were observed.Conclusion Exemestane is effective to treat bone metastasis of breast cancer with minor adverse reactions and good tolerability.

Objective To investigate the expression of Nestin and its relationship with tamoxifen cura-tive effect and prognosis of patients with breast cancer. Methods A total of 82 patients with breast cancer who received tamoxifen therapy after radical mastectomy in Department of Breast Surgery of Enshi Tujia Miao Auton-omous Prefecture Central Hospital of Hubei Province from March 2009 to March 2013 were collected. And the paired cancer tissues and adjacent normal tissues preserved in liquid nitrogen were also collected. Fluorescent quantitative real-time PCR( RT-PCR)and immunohistochemistry were used to detect the content of Nestin mRNA and the expression of Nestin in breast cancer tissues. The expression of Nestin in breast cancer tissues and its relationship with clinicopathologic features were analyzed. Breast cancer cell line MCF-7 was selected, small interfering RNA(siRNA)was used to silence Nestin in MCF-7 cells,and the influence on tamoxifen sen-sitivity was observed. The relationship of Nestin and epithelial-mesenchymal transition( EMT)was detected using Western blotting. Results The results of RT-PCR indicated that the mRNA level of Nestin in breast cancer tissues was 3. 87 times as high as that in paracancerous tissues(6. 34 ± 1. 56 vs. 1. 64 ± 0. 52,t =26. 140,P < 0. 001). Immunohistochemical staining suggested that the positive rate of Nestin in breast cancer tissues was 75. 61％(62 / 82),which was significantly higher than that in paracancerous tissues[24. 39％(20 / 82)],with a significant difference(χ2 = 43. 024,P < 0. 001). The expression of Nestin was related to lymphatic vessel infiltration(χ2 = 7. 499,P = 0. 006)and lymph node metastasis(χ2 = 6. 770,P = 0. 034), and it was not related to the age of patients(χ2 = 3. 242,P = 0. 072),tumor size(χ2 = 2. 358,P = 0. 308), histological grade(χ2 = 0. 294,P = 0. 863),ductal infiltrating status(χ2 = 0. 180,P = 0. 671)and triple neg-ative breast cancer(χ2 = 0. 142,P = 0. 706). The analysis of Cox risk ratio model showed that Nestin expres-sion(HR = 1. 982,P < 0. 001;HR = 1. 537,P < 0. 001),lymphatic vessel invasion( HR = 2. 502,P <0. 001;HR = 1. 715,P < 0. 001)and lymph node metastasis(HR = 1. 818,P < 0. 001;HR = 1. 446,P <0. 001)were independent prognostic risk factors for progress-free survival and overall survival in breast cancer patients. After Nestin knockout in breast cancer cell line MCF-7,the IC50 value of MCF-7 to tamoxifen de-creased from(48. 05 ± 2. 22)μmol/ L to(35. 59 ± 2. 92)μmol/ L,with a significant difference(t = 6. 489, P = 0. 003). Silencing Nestin significantly up-regulated E-cadherin(7. 21 ± 1. 15 vs. 1. 02 ± 0. 01,t = 6. 654, P = 0. 024)and down-regulated the mesenchyme index Vimentin(0. 17 ± 0. 08 vs. 1. 01 ± 0. 02,t = 25. 015, P < 0. 001)in MCF-7 cells. Conclusion Nestin is over-expressed in breast cancer,which is associated with reduced efficacy of tamoxifen. Nestin may be a new potential prognostic biomarker for breast cancer.