A summary of nuclear function of EGFR as a transcriptional co-activator. Nuclear EGFR can function in transcriptional regulation to enhance expression levels of target genes, including iNOS (A), cyclin D1 (B), COX-2 (C), Aurora-A (C), c-Myc (C), B-Myb (D), thymidylate synthase (E), and BCRP (E), through activation of transcriptional factors, such as STAT and E2F1. EGFR also associates with RHA in the nucleus, where the EGFR/RHA complex binds to the target gene promoter, including iNOS (A) and cyclinD1 (B), through the recruitment of RHA to the ATRS of the target gene promoter to mediate its transcriptional activation. In addition to RHA, EGFR is also recruited to the iNOS gene promoter through STAT3 to the STAT3-binding site (A). Whether RHA is involved in the nuclear EGFR-mediated activation of thymidylate synthase and BCRP (E) has not yet been explored.