B2M and polycystic ovary syndrome: Figure 3 shows that GUSB was ranked the most stably expressed reference gene with a SD (±Ct) and CV (%Ct) of 0.70 and 2.67, respectively, followed by RNA18S5 (SD: 0.40, CV: 2.87), HMBS (SD: 0.90, CV: 3.19), IPO8 (SD: 0.88, CV: 3.38), TFRC (SD: 0.85, CV: 3.45), POLR2A (SD: 0.88, CV: 3.58), HPRT1 (SD: 0.88, CV: 3.59), RPLP0 (SD: 0.75, CV: 3.77), RPL13A (SD: 0.75, CV: 3.97), YWHAZ (SD: 0.88, CV: 4.12), PGK1 (SD: 0.95, CV: 4.30), ACTB (SD: 0.76, CV: 4.36), UBC (SD: 1.00, CV: 4.72), B2M (SD: 0.93, CV: 4.73), and GAPDH (SD: 0.94, CV: 5.02), which was ranked the least stable gene in GCs from PCOS.