Clinical Significance of Serum p53 Antibody in the Early Detection and Poor Prognosis of Gastric Cancer

The aim of this retrospective study was to evaluate the clinical relevance of serum p53 antibody (S-p53Ab) as a biomarker and to investigate whether its diagnostic value could be improved when combined with other biomarkers of gastric cancer (GC).Serum samples were obtained preoperatively from 208 patients with histologically-confirmed GC, including 126 stage I patients (60.6%). Levels of S-p53Ab were assessed by a commercial laboratory using an anti-p53 detection kit. The cut-off value for S-p53Ab was 1.3 U/ml.S-p53Ab was detected in 16.3% (34 of 208) of patients with GC, including 13.6% (22 of 162) of patients with early-stage GC. The positive rates for S-p53Ab, carbohydrate antigen 19-9 (CA19-9), and carcinoembryonic antigen (CEA) of patients with stage I GC were 10.3% (13/126), 2.4% (3/126), and 8.7% (11/126), respectively. Positivity for S-p53Ab was not associated with CA19-9 or CEA positivity (p=0.098 and 0.053, respectively). The positive rate for a diagnosis of GC increased from 16.3% to 29.3% when S-p53-Ab was combined with CEA in this study. We found no significant correlation between the presence of S-p53Ab in GC and overall survival. Conversely, Cox regression analysis revealed that a high level of CA19-9 was an independent prognostic factor for GC in this series (hazard ratio(HR)=3.864; 95% confidence interval(CI)= 1.248-11.959; p=0.019). Kaplan-Meier analyses demonstrated significant differences in survival between patients with elevated levels of both S-p53Ab and CEA and those with elevated levels of only one or neither.The diagnostic rate of S-p53Ab was better than that of CA19-9 and CEA in patients with stage I GC. Combined detection of S-p53Ab and CEA may improve the diagnostic sensitivity and may permit more accurate stratification of GC patients.