A follicular fluid isobaric tags for relative and absolute quantitation (iTRAQ) proteome study of polycystic ovary syndrome (PCOS) patients revealed downregulation of complement components and dysregulation of proteins functionally associated with angiogenic processes, for instance, PLG, AGT, LYVE1 (pro-angiogenic), and SERPINA1 (an inhibitor of PLG; anti-angiogenic). This evidence concerns the gene SERPINA1 and polycystic ovary syndrome.