Clinical Value of Serum p53 Antibody in the Diagnosis and Prognosis of Esophageal Squamous Cell Carcinoma

Identifying useful biomarkers is central to selecting optimal therapeutic strategies for esophageal squamous cell carcinoma (ESCC). Serum p53 antibody (S-p53Ab), squamous cell carcinoma antigen (SCC-Ag), and carcinoembryonic antigen (CEA) were investigated to evaluate the significance of single and combined tumor markers in determining the diagnosis and prognosis of ESCC. Serum samples were obtained preoperatively from 133 patients with histologically-confirmed ESCC, including 32 patients with stage I (24.1%). Levels of S-p53Ab were assessed by enzyme-linked immunosorbent assay, using a new version of a highly specific, quantitative kit. The cut-off value for S-p53Ab was 1.3 U/ml. S-p53Ab was detected in 39.1% (52 out of 133) of patients with ESCC, including 40.0% (20 out of 50) of patients with early-stage ESCC. Positive rates for S-p53Ab, CEA, and SCC-Ag among patients with stage I ESCC (n=32) were 40.6%, 12.5%, and 31.3%, respectively. Positivity for S-p53Ab was not associated with positivity for CEA or SCC-Ag (p=0.249 and 0.747, respectively). The positive rate for diagnosis of ESCC increased from 39.1% to 65.4% when S-p53Ab was combined with SCC-Ag in this study. We found no significant correlation between the presence of S-p53Ab in ESCC and overall survival. Conversely, Cox regression analysis revealed that the International Union Against Cancer/TNM classification and systemic inflammation score were independent prognostic factors for ESCC in this series (hazard ratio(HR)=3.811, 95% confidence interval(CI)=1.548-9.378, p=0.004; and HR=2.218; 95% CI=1.087-4.523, p=0.029, respectively). Kaplan-Meier analysis revealed significant differences between patients with elevated S-p53Ab and SCC-Ag and patients with elevated levels of only one or neither of these factors (p=0.009). The diagnostic rate with S-p53Ab was better than that with SCC-Ag and CEA in patients with early-stage ESCC. Combined detection of S-p53Ab and SCC-Ag can markedly improve diagnostic sensitivity and may permit more accurate stratification of patients with ESCC.