ABCC2 and colorectal carcinoma: Moreover, co-transfection of SOX2 and β-catenin had a synergistic effect on ABCC2 promoter activity; knockdown of either β-catenin or SOX2 partly reduced ABCC2 promoter-driven luciferase activity and diminished the synergy between SOX2 and β-catenin; suggesting a functional linkage of SOX2 with β-catenin in the transcriptional regulation of ABCC2 in CRC (Fig. 2O).