Prognostic significance of p53-expression in colorectal carcinoma as measured by a luminometric immunoassay

Background: Mutations of the TP53 gene induce the production of abnormal p53-protein with a prolonged half-life allowing its detection by monoclonal antibodies. In the following study we examined if elevated levels of p53 correlate with worse prognosis in colorectal cancer. Methods: We have quantified the protein, using an immunoluminometric assay, in 144 cytosols of primary sporadic colorectal cancer tissues and in 96 specimen of normal mucosa. Results: In 112 samples (77.8%) the p53-expression was higher than the cut-off-value of 0.15 ng p53 per mg total protein. Luminometric immunoassay did not correlate with various clinicopathological parameters. Follow-up ranged from 2.4 to 54.3 (mean 25.3) months. During this period, 61 patients developed recurrences of whom 39 died of the underlying disease. Neither univariate nor multivariate analysis showed any statistically significant differences in prognosis between high and low p53 expression. Conclusion: Our investigation revealed that p53-overexpression as measured by a luminometric immunoassay, is not a useful predictor of prognosis in patients with colorectal adenocarcinoma. Overcoming the limit of semiquantitative immunohistochemistry for p53-protein quantitative immunoluminometry may be useful elucidating the relation between serum p53-antibodies and p53 in cytosols.