MTOR and ovarian hyperstimulation syndrome: Zhao et al. found that miR-16 expression was significantly lower in the serum of patients with PCOS and severe OHSS than in the serum of control subjects with mild or no OHSS; further studies demonstrated that miR-16 might help regulate vascular endothelial growth factor synthesis and the Akt/mTOR signalling pathway; furthermore, receiver operating characteristic curve analysis suggested that the serum miR-16 level has a higher predictive value for OHSS than the Body Mass Index, serum luteinizing hormone (LH) level, and LH/FSH ratio [31].