Abstract:Objective To study the expressionofSIRT1 in breast cancer with diabetes mellitus，and analyze the correlationbetween SIRT1and p53，and analyze blood lipiddifferences in breast cancer tissue without diabetes mellitus and breast cancer tissue with diabetes mellitus，and to research its relation with type 2 diabetes mellitus and assesse the clinical value. Methods Immunohistochemistry was used to examine the expressions of SIRT1 and p53 in 30 breast cancer patients with diabetes mellitus and 30 breast cancer patients withoutdiabetic mellitus, and their correlation was analyzed. Results The positive rate of SIRT1 in breast cancer tissue with diabetes mellitus was significantly lower than that in breast cancer tissue withoutdiabetic mellitus（P<0.05）.In SIRT1 positive tissue, the expression level of p53 tissue was significantly higher than that in SIRT1 negative tissue（P<0.05）.The expression of SIRT1 was significantly positively related with p53 expression in breast cancer tissue with diabetes（P<0.05）. BMI and TG in breast cancer group with diabetes mellitus were significantly higher than those in breast cancer group withoutdiabetic mellitus（P<0.05）, but HDL was lower(P=0.05).However, CHO and LDL had no significant differences in both groups(P>0.05). Conclusions SIRT1 is up-regulated in breast cancer, but the positive rate of SIRT1 in breast cancer tissue with diabetes mellitus is significantly lower than that in breast cancer tissue withoutdiabetic, and is associated with the progression of diabetes mellitus. SIRT1 protein is significantly positively correlated to p53 expression and it may be involved in the adjustment process of blood lipids, SIRT1 might be a new biological targetin diabetes andbreast cancer.