Detection of circulating anti-p53 antibodies in patients with colorectal carcinoma and the antibody's relation to clinical factors

Mutation of the p53 tumor suppressor gene is the most common genetic alternation in colorectal carcinoma and is assessed mainly by molecular analysis of the gene sequence or by immunohistochemical analysis of p53 protein accumulation. Purpose of this study was to detect circulating antibody against p53 proteins in serum of patients with colorectal carcinoma and to evaluate its clinical significance. We used immunoblotting techniques to detect circulating anti-p53 antibodies. Relationship among staging, immunohistochemical expression of p53 in the primary tumor, and serum carcinoembryonic antigen level was investigated. Circulating anti-p53 antibodies were detected in 32 (68 percent) of 47 patients. Antibody was found in patients at all clinical stages of disease. In 33 patients whose sera and primary tumor tissues were available for testing, 16 (48 percent) were positive for both circulating anti-p53 antibody and p53 expression in the tumor. The anti-p53 antibody test was positive in 78 and 56 percent of patients with high and normal serum carcinoembryonic antigen levels, respectively. Detection of anti-p53 antibodies may become a new diagnostic indicator of colorectal carcinomas.