The mRNA expression levels of these genes from the FF exosomes were examined in our study, and the results showed significantly increased CYP11A, CYP19A and HSD17b1 mRNA expression in the PCOS group (Fig. 4), indicating that the increase in E2 was associated with increased expression of key genes involved in hormone synthesis. The gene discussed is CYP11A1; the disease is polycystic ovary syndrome.