POP4 and polycystic ovary syndrome: To further validate our lncRNA profiling results and determine the biological function of lncRNAs in the development of PCOS, nine lncRNAs (lncRNA-H19, lncRNA-POP4, lncRNA-DICER1, lncRNA-PTEN, lncRNA-AKT3, lncRNA-HDAC6, lncRNA-NF1, lncRNAMUM1, and lncRNA-LINC00173) were preliminarily screened by RT-qPCR according to a lncRNA expression differential multiple value >10 and a P < 0.0001 in follicular fluid exosomes from 25 randomly chosen PCOS patients and 25 non-PCOS patients.