TRIB1 and anaplastic large cell lymphoma: Positive signals were observed in three of four different regulatory regions of the BCL2A1 gene, two of three locations within the G0S2 gene and two of seven locations within the S100A9 gene, whereas C/EBPβ binding was detected in a single regulatory region of TRIB1 and DDIT4. Surprisingly, no signals were detected analyzing the predicted DDX21 sites, although DDX21 was a promising candidate gene for direct regulation by C/EBPβ because of its high mRNA and protein expression and strong correlation with C/EBPβ expression in ALK+ ALCL cells.