CTCF and digestive system neoplasm: In the right-sided colon tumors, PKHD1 co-occurred with ARID1B, ARID2, B2M, CTCF, FAT1, FLT1, FLT3, and PDE11A, most of which were DNA damage genes, whereas KRAS was found mutually exclusive with ARID1B (Figure 4D).