E2F4 and malignant colon neoplasm: We also examined the remaining promoter region (-492/+115 bp) after deletion of the six TBEs for the presence of binding sites of other transcription factors, such as AP-2, C2H2 zinc finger, E2F4, EGR1, ETS1, and serum response factors (data not shown), several of which are known to play an important role in colon cancer.