GREM1 and polycystic ovary syndrome: Basing our conclusion on the most predominant tendency determined in the studies, we may speculate that the concentrations of the markers preptin, gremlin-1, galectin-3, neuregulin-4, xenin-25, xenopsin related peptide in serum may be elevated, while those of nesfatin-1, myonectin, omentin-1, neudesin may be decreased in PCOS individuals.