Zhou D, et al. - The levels of progranulin (PGRN) in follicular fluid (FF) and the expression of PGRN in granulosa cells (GCs) regarding the quality of the oocytes both in patients with polycystic ovary syndrome (PCOS) and in the normal ovary amid COH cycles are assessed in this study. The outcome of this study suggests that PGRN may be a crucial determinant of fertilization success for PCOS patients.