An editorial decision has been made to retract this manuscript due to breach of publishing guidelines, following the identification of non-original and manipulated figures. Reference: Fengli Zhang, Huixiao Chen, Jing Du, Bin Wang, Lixiao Yang: Anticancer Activity of Metformin, an Antidiabetic Drug, Against Ovarian Cancer Cells Involves Inhibition of Cysteine-Rich 61 (Cyr61)/Akt/Mammalian Target of Rapamycin (mTOR) Signaling Pathway. Med Sci Monit 2018; 24: 6093-6101. 10.12659/MSM.909745.