ESR1 and cancer: Additionally, a strong correlation between ER and changes in chromatin looping interactions has been reported in both breast (Fullwood et al. 2009; Gomez Acuna et al. 2024) and endometrial (La Greca et al. 2022) cancer cells, suggesting that ER may play a role in mediating 3D genome structure alterations in response to estrogen treatment or that it may utilize changes in chromatin looping to impact transcription.