MicroRNAs 103 and 107 link type 2 diabetes and post-menopausal breast cancer

Type 2 diabetes mellitus (T2DM) increases the incidence of post-menopausal breast cancer (PMBC). This study is intended to determine whether microRNA-103/107 (miR-103/107) should be regarded as a potential molecular link between T2DM and PMBC. Samples of serum from 90 patients with T2DM and/or PMBC were collected. Samples of serum from 20 non-diabetic post-menopausal women were used as the control. The body mass index (BMI) of patients with T2DM and PMBC was lower than the BMI of patients with only T2DM or PMBC (p < 0.05). The expression of miR-103/107 was higher in the serum of T2DM patients compared with that in control samples (2.80 ± 0.46/36.29 ± 3.41 vs 0.88 ± 0.25/8.59 ± 1.91, p < 0.05). The expression of miR-103/107 in the serum of PMBC patients was higher than that in T2DM patients (5.06 ± 0.92/49.59 ± 6.99 vs 2.80 ± 0.46/36.29 ± 3.41, p < 0.05) but lower than that in patients diagnosed with both T2DM and PMBC (7.67 ± 0.87/63.24 ± 8.58, p < 0.05). miR-103/107 was positively correlated with the homeostasis model assessment-insulin resistance (HOMA-IR) index (r = 0.71, 0.685, p < 0.01). The expression of miR-103/107 was an independent factor of the HOMA-IR index (β = 0.638, 0.073, p = 0.02, 0.01). There were higher levels of estradiol (E2) in patients with T2DM and/or PMBC than that in the control group. High expression of miR-103/107 results in insulin resistance and is associated with overweight or obese patients with T2DM and PMBC through elevated levels of E2. miR-103/107 may be a potential molecular link between T2DM and PMBC.