ASCL1 and colorectal carcinoma: We also observed downregulation in RNA expression and the surrounding H3K27ac marks of the basic-helix-loop-helix (bHLH) transcription factors ASCL1 and HAND1 that are usually strongly expressed in proliferating neuroblasts (Figure 6B).55 These data suggest that combining PB and RA has a much greater effect on CRC gene expression than PB alone.