ELK1 and nonpapillary renal cell carcinoma: However, the 5′-flank of the FFA1 gene contains a variety of conserved transcription factor binding sequences that readily regulate FFA1 expression, including AP2, STAT, IK2, PEA3, PBX, Bel1 and MEIS1, as well as the common transcriptional repressors AP4, ETS, RFX, EV1, ELK1, GATA [68], which we hypothesize are responsible for alteration of FFA1 expression in pRCC and ccRCC described here.