Diamanti-Kandarakis et al. reported lower serum levels of neutrophil gelatinase-associated lipocalin (NGAL) and MMP-9/NGAL, suggesting lower levels of MMP-9 in women with PCOS compared to the age- and BMI-matched controls, both in the lean and overweight PCOS cohorts. This evidence concerns the gene LCN2 and polycystic ovary syndrome.