Abstract

BACKGROUND: Colitis associated dysplasia and cancer often have deletions involving the long arm of chromosome 18q, suggesting the location of a tumour suppressor gene critical for their tumorigenesis. The DPC4 gene, which is genetically inactivated in pancreatic and other cancers, has recently been described. AIM: Because DPC4 is located at 18q21.1, the hypothesis that it could be a mutated tumour suppressor gene in colitis associated neoplasms was tested. PATIENTS: Advanced neoplastic lesions from six patients having chronic colitis were analysed for DPC4. METHODS: Individual exons of DPC4 were amplified by the polymerase chain reaction (PCR) and sequenced from genomic DNA of tissue specimens dissected by cryostat. RESULTS: DPC4 was found to have biallelic inactivation in one of three neoplasms shown to have allelic loss of 18q. The mutation had been acquired somatically in a plaque of high grade dysplasia. The mutation created a non-sense codon, which would cause premature termination of protein translation. CONCLUSION: The DPC4 gene is a target of 18q LOH events in colitis associated neoplasia.