CTCF and polycystic ovary syndrome: Notably, CTCF, a key transcription factor, is critically involved in PCOS initiation and progression.62 We found that CTCF mRNA expression was reduced in nPKM2 cells and was downregulated in some patients with PCOS; most importantly, the Ctcf mRNA level was low in the GCs of PCOS-like mice, and TEPP-46 could partially rescue its expression levels (Supplementary Fig. 10b).