Among the 89 samples, RNA18S5 and ACTB were the most abundant genes, followed by GAPDH, while the least abundant gene was HMBS. The assessed reference genes showed significant inter-individual variations across the samples, with SD values ranging from 0.54 for RNA18S5 to 1.26 for UBC. Thus it is clear that a vigorous test is required to evaluate the reliability of the 15 candidate reference genes for use as internal controls for comparative gene expression normalization in GCs from PCOS patients. Here, HMBS is linked to polycystic ovary syndrome.