Significance of SIRT1 expression in breast cancer

Objective To investigate the expression of SIRT1 and its association with clinicopathologic features in breast carcinoma with type 2 diabetes mellitus. Methods The expression of SIRT1 in 30 breast cancer with type 2 diabetes mellitus, 65 samples of breast cancer without diabetes mellitus and 18 samples of corresponding normal breast tissues was investigated using immunohistochemistry.Results The positive rate of SIRT1 in breast cancer tissues was significantly higher than that breast cancer with type 2 diabetes mellitus and normal breast tissue (P ＜0.05). In breast cancer with type 2 diabetes mellitus group. The positive rate of SIRT1 was significantly higher than that normal breast tissue (P ＜0.05). The expression of SIRT1 was positively correlated with the number of lymph node (P =0.011), pTNM tumor stage (P =0.028), p53 (P =0.003) and Her-2 (P =0.031) in breast cancer with type 2 diabetes mellitus group. The expression level of SIRT1 in lymph node-positive group was higher than that in lymph node-negative group (P ＜0.05). The expression level of SIRT1 was in lymph node-positive group was higher than that in lymph node-negative group (P ＜0.05). Conclusion SIRTI was up-regulated in breast cancer with type 2 diabetes mellitus, but its expression was lower than that breast cancer without diabetes mellitus, and was associated with the progression of diabetes mellitus. SIRT1 was positively correlated with lymph node, pTNM tumor stage,p53 and Her-2, SIRT1 may be a novel biological parameter to evaluate the malignant degree of breast carcinoma and to predict prognosis of breast cancer. Key words: Breast neoplasms;  SIRT1;  Gene, p53;  Diabetes mellitus, Type 2