Loss of microRNA-145 expression is involved in the development and prognosis of breast cancer complicated by type 2 diabetes mellitus

Objective: To explore the relationships of the expression of miR-145 to the clinicopathological characteristics and prognosis of patients with breast cancer complicated by type 2 diabetes mellitus (T2DM). Methods: A total of 257 female patients with breast cancer were enrolled for our experiment, including 140 patients with simple breast cancer (control group) and 117 patients with breast cancer complicated by T2DM (observation group). Patients were treated with modified radical mastectomy supplemented with radiotherapy, chemotherapy and endocrine therapy. qRT-PCR was used for the detection of miR-145 expression in patients of both groups. Follow-up lasted 13-60 months. Results: The relative expression of miR-145 in the observation group was significantly lower than that in the control group (p<0.05). The expression of miR-145 in patients with breast cancer complicated by T2DM was related to the history of diabetes, tumor node metastasis (TNM) stage, tumor size, lymph node metastasis (LNM), estrogen receptor (ER) status, and HER2 (all p<0.05). The median disease-free survival (DFS) was significantly longer and the 5-year DFS rate significantly higher in the high-expression group than in the low-expression group. History of diabetes, TNM stage, tumor size, LNM, ER status, and HER2 were risk factors for patients with breast cancer complicated by T2DM (all p<0.05). Conclusions: Loss of miR-145 expression is related to the development of breast cancer complicated by T2DM, and low miR-145 expression might be an adverse prognostic factor in patients with this disease.