Prognostic significance of serum p53 antibody according to KRAS status in metastatic colorectal cancer patients

Background Serum anti-p53 antibody is used clinically as a tumor marker of colorectal cancer. However, its prognostic significance in patients with metastatic colorectal cancer (mCRC) remains unclear. KRAS status may influence the host immune response against tumor progression. In the present study, we investigated the prognostic significance of serum anti-p53 in mCRC patients with wild-type KRAS and mutant KRAS treated with systemic chemotherapy. Methods A retrospective study of 150 mCRC patients in whom serum anti-p53 antibody was measured before first-line chemotherapy was conducted. The patients were divided into two groups, high p53 and low p53, based on their serum anti-p53 antibody levels. Associations between serum anti-p53 level and clinical outcomes were evaluated in conjunction with KRAS status. Results There were 97 (64.7%) patients with wild-type KRAS and 53 (35.3%) with mutant KRAS. In an analysis of all patients, there was no significant difference in overall survival (OS) between the high p53 and low p53 groups. In patients with mutant KRAS, those in the high p53 group exhibited significantly longer OS than those in the low p53 group (p = 0.017, log-rank test). In the multivariate analysis, serum p53 antibody level was an independent predictor of OS in mCRC patients (high vs. normal; hazard ratio 0.438, 95% confidence interval 0.178-0.974, p < 0.05). Conclusions Serum anti-p53 antibody level may be an independent predictor of OS in mCRC patients with KRAS mutant tumors.