Editor,—We read the paper by Hammel et al (Gut 1997;40:356–61) with interest. The authors studied antibodies to the p53 tumour suppressor gene product in serum of patients with colorectal cancer and reported a p53 positive patient (CC49) who developed colorectal cancer after a history of >10 years of ulcerous pancolitis. Hammel et alstated that p53 tumour suppressor gene mutations are frequent abnormalities in colorectal cancer. p53 mutations can lead to the accumulation of the p53 gene product in the cell and thus may trigger an antigen driven humoral response against …