YY1 and neoplasm: Given that YY1 is upregulated while YY2 is downregulated in tumor cells, our results indicate that both an upregulation of YY1, which consequently impaired YY2 binding to the SLC7A11 promoter, and a downregulation of YY2 in tumor cells might enhance SLC7A11 expression and antioxidant defenses, and favor tumorigenesis.