ASCL1 and colorectal carcinoma: During ATRA treatment, the mRNA levels for adrenergic CRC transcription factor genes that are not also components of the retino-sympathetic CRC—MYCN, PHOX2B, GATA3, and ASCL1—fell precipitously by day 1, fell a little further by day 3, and then increased slightly by day 6 (Fig. 7A).