CRLF2 and acute lymphoblastic leukemia: Here we observed that IKZF1 binds to the promoter region of CRLF2 and directly suppresses the promoter activity of CRLF2. Our data provide evidence that IKZF1 suppresses CRLF2 expression and conversely, that IKZF1 knockdown increases CRLF2 expression in ALL cells.