P53 Autoantibodies in Sera of Patients with a Colorectal Cancer and Their Association to P53 Protein Concentration and P53 Immunohistochemistry in Tumor Tissue

We evaluated p53 autoantibodies (p53-Ab) as a preoperative tumor marker and as a prognosis marker. We also investigated whether p53-Ab production is dependent on p53 protein overexpression in tumor tissue or on tumor volume. Serum samples of patients with a colorectal cancer (n = 130) and of healthy controls (n = 44) were examined for p53-Ab using an ELISA kit. P53 protein expression in tumor tissue was demonstrated immunohistochemically and quantified by ELISA. Tumor volume was calculated and patients' survival computed using the Kaplan-Meier method. p53-Ab were detected in the serum from 15% of patients; all controls were negative. There was a significant correlation between p53-Ab production and positive immunostaining or p53 protein concentration in tumor tissue. p53-Ab were detected at a higher percentage of patients with a tumor volume of 10 cm3 or greater than in those with a smaller tumor. No difference in patients' prognosis was found between the p53-Ab positive and negative groups. Because of their low sensitivity (15%) p53-Ab are not suitable as a preoperative tumor marker. However, their high specificity (100%) and their potential for early diagnosis of a tumor relapse makes them valuable for postoperative monitoring during follow-up in p53-Ab positive patients. Furthermore, their detection can be used as a simple serological test for early detection of p53 alterations.