HMBS and polycystic ovary syndrome: As shown in Fig. 4A, in contrast to the GeNorm and BestKeeper results, NormFinder ranked HPRT1 as the most stable reference gene with an M-value of 0.07, followed by YWHAZ (0.09), ACTB (0.42), HMBS (0.11), PGK1 (0.11), UBC (0.12), GAPDH (0.19), GUSB (0.2), IPO8 (0.21), POLR2A (0.22), RPLP0 (0.24), RNA18S5 (0.24), TFRC (0.25), RPL13A (0.25), and B2M, which, with the highest M-value of 0.28, was ranked as the least stable gene in GCs from PCOS patients.