The tryptophan clusters within the family of HTH containing transcription factors comprise several tryptophan residues with a spacing of 12-21 amino acid residues; the subclass of myb-type DNA-binding domains typically exhibit a spacing of 19-21 amino acid residues. The ETS family (E26 transformation-specific), a group of 29 transcription factors containing tryptophan clusters, can be divided in 12 subfamilies which all share the feature that they bind a central GGA(A/T) DNA sequence. Many ETS-domain transcription factors are known to represent nuclear targets of signalling pathways. In particular, the MAPK pathways have been linked with a diverse series of regulatory events that involve ETS-domain proteins[1]. The closely related TFs ERG and ETV1 are frequently found to be involved in protein fusions causing, or playing a crucial role in, prostate cancer[2].