CDX2 and colorectal cancer: To confirm these findings in a more physiologic setting, we used retroviral transduction to over-express either EGFP, CDX2, or CDX2/AS in HT29 and SW480 colorectal cancer cells that express endogenous CDX2 and CDX2/AS (Fig. 1E) and compared expression of endogenous GUCY2C transcripts (Fig. 3C).