KRAS and in situ carcinoma: Further, when we stratified mutation frequency for low- and high-grade adenoma, the distribution was as follows: low-grade adenoma—high-grade adenomas- in situ carcinoma: APC gene 42.9–56.0–54.5%; KRAS gene 32.7–32.0–45.5%; TP53 gene 8.2–20.0–18.2%.