Immunohistochemical staining of p53 was performed using an anti-p53 mouse monoclonal antibody, Pab1801, on 67 colorectal adenocarcinoma specimens to determine the prognostic value of p53 in colorectal cancer patients. Of a total of 67 tumors examined, p53 was detected in 34, but the rate of positive staining for p53 did not correlate with the clinical stage of disease. In 59 patients undergoing curative resection of the tumor, there was no significant difference in the recurrence rate (P = 0.137) or the disease-free survival rate between 28 patients with p53 positive tumors and 31 with p53 negative tumors (P = 0.135).