ESR1 and hepatocellular carcinoma: In previous studies, we have reported that, comparing nontumoral, cirrhotic and malignant liver tissues, an increasingly higher aromatase expression and activity is strictly associated with a progressive reduction of the wild type ERα (Erα66) and the gradual emergence of the ERα36 splicing variant, suggesting that this ER shift could be distinctively implicated in HCC development and progression [54,55].