SOX9 and colorectal carcinoma: Interestingly, the majority of SOX9 mutations in the MMR-D CRC were missense or nonsense and did not occur in mononucleotide tracts, while only 2 of the 10 SOX9 mutations in these 6 MMR-D, SOX9 mutant CRC were frameshifts (both in mononucleotide tracts).