E2F6 and neoplasm: Moreover, by evaluating the enrichment of known binding motifs in their promoter regions, this set of 26 tumor-recurring switch genes appeared to be putatively co-regulated by the nuclear transcription factor Y (NF-Y) family (NF-YA, NF-YB) and the E2F transcription factor family (E2F4/E2F6), known to participate in the regulation of progression through the cell cycle.