RPL13A and polycystic ovary syndrome: As shown in Fig. 2B and C, the V2/3 value is just over the cutoff threshold of 0.15 with an expression ratio of 0.1536 (r2 = 0.978), while the V3/4 value was below the cutoff with an expression ratio of 0.1047 (r2 = 0.986), indicating that the top three ranked reference genes RPL13A, RLPP0, and ACTB (with the lowest M-values) were suggested for gene expression normalization in GCs from PCOS patients.