HES6 is a transcription cofactor that iteself does not bind to DNA but suppresses both HES1-mediated N box-dependent transcriptional repression and binding of HES1 to E box sequences. It also suppresses HES1-mediated inhibition of the heterodimer formed by ASCL1/MASH1 and TCFEA2/E47, allowing ASCL1 and TCFEA2 to upregulate transcription in its presence. HES6 appears to have novel functions in tumour and cancer cell lines, although these have not yet been elucidated fully.