TP53 and ulcerative colitis: Compared to the sporadic carcinoma case, p53 gene mutations are more frequent in early stages of tumorigenesis, being found in low-grade dysplasia (LGD) or non-neoplastic regenerative mucosa with ulcerative colitis (Chaubert et al, 1994; Holzmann et al, 1998; Takaku et al, 2001).