ELK1 and hepatocellular carcinoma: To demonstrate that SRF, ELK1, and ELK4 indeed effectively induce the transcription of the MDM4 gene, the specific siRNAs targeting SRF, ELK1, and ELK4, together with an MDM4 promoter construct carrying a Gaussia luciferase as reporter, were transiently transfected in HCC cells.