Evaluation of an immunoluminometric based assay as a novel method for the quantitative analysis of p53 protein in tumor tissues

Objective: This study aims at evaluating a novel luminometric immunoassay in the measurement of wildtype and mutant p53 protein in extracts from colorectal tumor tissues. Methods: p53 accumulation in human primary colorectal carcinoma was studied by applying both quantitative luminometric immunoassay, and semi quantitative immunohistochemistry analysis, whereas p53 gene alterations, in exons 5-8, were examined by single strand conformation polymorphism analysis. Results: Sixty five samples out of 120 colorectal tumor samples showed positive p53 values that exceeded 1.8 ng/ mg protein (cut-off value) by luminometric immunoassay-mat. An overall correlation of 89% was found between immunohistochemistry analysis and luminometric immunoassay. p53 gene alteration was identified by using polymerase chain reaction/single strand conformation polymorphism in 22 out of 42 (52%) tumor samples. Despite a significant correlation between the outcome of luminometric immunoassay and single strand conformation polymorphism, a disagreement was found in 30% of cases. Conclusion: Our data demonstrates that the new p53 luminometric immunoassay is sensitive, quantitative, and it yields reliable estimate of p53 expression in cytosol samples as compared with results obtained from other methods such as immunohistochemistry analysis and polymerase chain reaction/single strand conformation polymorphism.