Metformin is a first-line drug treatment for typeⅡdiabetes. Recent studies have showed that metformin can upregulate CycG2, induce mitochondria-mediated accumulation of reactive oxygen species (ROS), and inhibit the activity of transforming growth factor-β (TGF-β). Metformin could protect metastasis of nondiabetic breast cancer, and may become a chemopreventive drug for breast cancer. This review aims to clarify the inhibitory mechanism of metformin on the breast cancer and the drug resistance of metformin according to basic and clinical study.

Objective To investigate the effect of enteral microecopharmaceutics nutrition supplement (EMN) on incidence of ventilator associated pneumonia complications,inflammatory responses,and prognoses in patients with severe traumatic brain injury (sTBI) undergoing ventilator therapy.Methods From January 2016 to September 2017,70 patients with sTBI were randomly divided into an experimental group (EMN supplement,n=35) and a control group (n=35).Early enteral nutrition was given to patients from both groups,and bifidobacterium viable capsule was given to patients from the experimental group.Glasgow Coma Scale (GCS) scores,acute physiological and chronic health evaluation (APACHE) II scores,number of white blood cells (WBC),proportion of neutrophil (N),and serum levels of procalcitonin (PCT) and C-reactive protein (CRP) were compared between the two groups on admission and 14 d after treatment.The incidence of VAP and clinical pulmonary infection scale (CPIS) scores,pulmonary function,mechanical ventilation time and hospital stays were compared 14 d after treatment.Results The incidence of VAP in the experimental group (n=17,51％) 14 d after EMN supplement was significantly lower as compared with that in the control group (n=22,63％,P＜0.05).Meanwhile,VAP patients from the experimental group had significantly lower CPIS scores as compared with patients from control group (P＜0.05).Ventilator weaning was achieved in 29 patients from experimental group (83％) and 24 patients from control group (69％),with significant difference (P＜0.05);ventilator weaning patients from the experimental group had significantly improved lung function as compared with ventilator weaning patients from control group (P＜0.05).WBC number,N proportion,and serum PCT and CRP levels in the experimental group were significantly smaller/decreased as compared with those in the control group (P＜0.05).As compared with patients from control group,patients from the experimental group had significantly higher GCS scores (8.35±0.51 vs.9.48±0.48,P＜0.05) and significantly lower APACHE II scores (12.58±0.78 vs.14.68±0.97,P＜0.05).Conclusion EMN supplement can effectively reduce the VAP incidence,alleviate the degree of infection and inflammatory response in patients with sTBI undergoing ventilator therapy,therefore,improve the prognosis;this method is worth of promotion.