Several of the proteins now identified in pregnant women with PCOS have been reported to be differentially expressed in non-pregnant women with PCOS as well, including increased levels of insulin growth factor II (IGF2), platelet factor 4 (PF4), serum amyloid A (SAA), fibulin-1 (FBL1), apolipoprotein A4 (APOA4) and alpha-1B-glycoprotein (A1BG) and decreased levels of zinc-alpha-2-glycoprotein (AZGP1) and serum paraoxonase/arylesterase 1 (PON1)23–27. Here, A1BG is linked to polycystic ovary syndrome.