ELK1 and hepatocellular carcinoma: To test for the physical interaction between the three TF candidates and the MDM4 promoter sequence in HCC cell lines, ChIP experiments were performed as outlined in Figure 4A. Specific binding of SRF, ELK1, and ELK4 were detected at their respective TF binding sites in the MDM4 promoter in both HepG2 and HLE cells (Figure 4B).