Clinical significance of serum anti-p53 antibody expression following curative surgery for colorectal cancer.

The aim of the present study was to investigate the usefulness of serum anti-p53 antibody (Ap53Ab) measurement for the diagnosis of colorectal cancer (CRC), and the clinical significance of the association between Ap53Ab expression and survival rate. Ap53Ab, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA)19-9 were measured by ELISA in 674 CRC patients and 115 healthy volunteers (control group). The half-life time of Ap53Ab and CEA was calculated. The association between positive Ap53Ab expression and clinicopathological characteristics, including survival rate, was analyzed. Of the 674 CRC patients, 195 (28.9%) were positive for Ap53Ab expression, while the positive rates of CEA and CA19-9 level were 39.9 and 16.9%, respectively. Positivity for Ap53Ab alone was observed in 94 patients (13.9%), whereas the positivity rate of any markers examined was 58.7%. The mean half-life of Ap53Ab and CEA was 30.7 and 11.3 days, respectively. Positive expression of Ap53Ab was significantly associated with the depth of tumor invasion (P<0.001), lymph node metastasis (P=0.024), stage (P<0.001) and CEA level (P=0.005). No significant correlation between Ap53Ab expression and poor survival rate was observed. The positive rate of Ap53Ab was higher compared with that of CEA and CA19-9 in early-stage CRC. The combination of these markers improved the diagnostic yield of CRC up to ~60%. Furthermore, Ap53Ab expression was associated with lymph node metastasis, but not with shorter survival. These results indicated that the measurement of Ap53Ab may contribute to increased rate of detection of CRC, particularly in patients with early-stage disease, in clinical practice.