To identify potential transcription factors that are involved in the aberrant up-regulation of Asef in colon tumors, we searched for transcription factor-binding motifs that are common to the promoter regions of the three Asef isoforms: Asef-a (Genbank AB042199), -b (Refseq NM_015320) and -c (NM_032995) (Figure S2). This evidence concerns the gene ARHGEF4 and colonic neoplasm.