Sequence-specific transcriptional activator (PubMed:24100448, PubMed:26316623, PubMed:28255014). Recognizes the DNA sequence 5'-C[CA]GGAAGT-3'. Can form homodimers or heterodimers with ETV6/TEL1. The gene represented in this entry is involved in disease pathogenesis. A chromosomal aberration involving FLI1 is found in patients with Erwing sarcoma. Translocation t(11;22)(q24;q12) with EWSR1. The disease is caused by variants affecting the gene represented in this entry. Located on a fragment of chromosome 11 flanked on the centromeric side by the acute lymphoblastic leukemia-associated t(4;11)(q21;q23) translocation breakpoint and on the telomeric side by the Ewing- and neuroepithelioma-associated t(11;22) (q24;q12) breakpoint. Belongs to the ETS family.