The down-regulation of both CYP11A1 (encoding cytochrome P450 cholesterol side-chain cleavage enzyme, or P450SCC) and HSD17B1 (encoding 17β-hydroxysteroid dehydrogenase enzyme, or 17-βHSD) and up-regulation of SULT1E1 (sulfotransferase Family 1E Member 1) mRNA expression are observed in mural luteinized GC of PCOS as compared to non-PCOS women [93]. Here, HSD17B1 is linked to polycystic ovary syndrome.