PIK3CA and colorectal carcinoma: Additionally, based on Table 2 and Fig. 2, apart from APC, genes that are frequently mutated include ARID1A, PIK3CA, SMAD4 and TCF7L2. These genes were in WNT, TGFβ and PI3K pathways, which were reported to play an important role in CRC tumorigenesis and differentiation.