Impact of Metformin on Cancer Biomarkers in Non-Diabetic Cancer Patients: A Systematic Review and Meta-Analysis of Clinical Trials. - Farkhondeh, Tahereh; Amirabadizadeh, Alireza; Aramjoo, Hamed; Llorens, Silvia; Roshanravan, Babak; Saeedi, Farhad; Talebi, Marjan; Shakibaei, Mehdi; Samarghandian, Saeed (Current Oncology, 2021)