ELK4 and cancer: Although ELK4 has been implicated in proliferation and cancer (19) and has engaged in the transcriptional response to 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced fibroblast cell activation and zymosan-induced macrophage activation (20, 21), the extent to which the immediate-early transcriptional response to FcεRI and GPCR mediated activation in mast cells is ELK4-dependent and the target genes involved have not been systematically investigated.