p53 immunoreaction in endoscopic biopsy specimens of colorectal cancer, and its prognostic significance.

The expression of p53 protein was immunohistochemically studied in formalin-fixed paraffin-embedded biopsy specimens of 203 colorectal carcinomas by use of a monoclonal antibody specific for the p53 protein. PAb1801. p53 protein expression with its reactivity localised in nuclei was found in 121 (59.6%) of the cancers. There was no correlation of p53 immunoreactivity with histological classification, wall invasion, lymphatic invasion, venous invasion, lymph node metastases, or peritoneal metastases. p53-positive cancers were more frequently associated with liver metastasis than p53-negative ones. Patients with p53-positive tumours had significantly poorer prognoses than those with p53-negative tumours. The 5 year survival rate was 58.1% for patients with p53-positive tumours, and 76.3% for those with p53-negative tumours. In Dukes' stage C tumours, an especially good correlation was found between p53 immunoreactivity and prognosis. In addition, patients with p53-positive tumours had higher recurrence rates. The results indicate that p53 immunoreactivity may be a useful prognostic marker of colorectal cancers.