The function of ELF2 (E74 like ETS transcription factor 2, Ensembl gene identifier ENSG00000109381) is as follows. Isoform 1 transcriptionally activates the LYN and BLK promoters and acts synergistically with RUNX1 to transactivate the BLK promoter. Isoform 2 may function in repression of RUNX1-mediated transactivation.