Mutated p53 in tumors, mutant p53 and p53-specific antibodies in the circulation in patients with gastric cancer

The accumulation of mutated p53 in tumor cells results in the presence in t he circulation of mutant p53 (p53m) and the production of p53-specific anti bodies (p53Ab). We examined the relationships among these phenomena and ana lyzed their clinical implications in 62 patients with gastric cancer at var ious stages. Expression of p53 in tumors was studied by an immunohistochemi cal method and circulating p53m and p53Ab were quantitated with commerciall y available enzyme-linked immunosorbent assay kits. The detectable expression of p53 in tumors and circulating p53Ab was recogn ized in 28 (45.2%) and 7 (11.3%) of the 62 patients, respectively. The numb er of patients with higher levels of circulating p53m increased with the pr ogression of the depth of cancer invasion. Patients with any positive findi ngs for the three p53-related parameters had a poorer prognosis, and the di fference was statistically significant in patients with p53Ab. When surviva l was analyzed in terms of the combination of the three p53-related paramet ers (detectable expression of p53 in tumor cells, high levels of p53m and p 53Ab in the circulation), a significantly poorer prognosis was associated w ith an increase in the number of positive parameters. Analysis of p53 in tumor cells, together with analysis of circulating p53m and p53Ab, could improve the accuracy of prognosis in patients with gastric cancer.