Clinical impact of perioperative changes of serum p53 antibody titers in patients with esophageal squamous cell carcinoma

4583 Background: The p53 protein overexpression that usually results from genetic alterations has been reported to induce serum antibodies against p53 in patients with esophageal squamous carcinoma. The clinical features of serum p53 antibodies (s-p53 Abs) are early negative conversion after curative treatment and patients who do not seroconvert to negative having a small number of residual cancer cells that remain after surgery. However, there is little information about the clinical significance of perioperative changes of s-p53 Abs titers in esophageal carcinoma. Methods: Our domestically developed highly specific enzyme- linked immunosorbent assay kit (MESACUP anti-p53 TEST) was used to analyze s-p53 Abs in 110 patients with esophageal carcinoma before and after surgery. The cutoff level of 1.3 U/mL was used to indicate seropositive patients. One month after surgery, s-p53 Abs titers were followed up to evaluate clinical impact of changes of serum titers. After surgery, all patients were monitored until the end of October 2007 or their death by clinical examinations on a regular basis. Recurrent disease was treated according to the standard methods. Prognostic impact of postoperative s-p53 Abs was evaluated in univariate and multivariate analyses. Patients recruitment and sample collections were performed within the guideline of protocols by the institutional review board. Results: A total of 40 (36%) patients were positive for s-p53 Abs before surgery. Serum titers were significantly reduced after surgery (3.1±4.8 vs 2.7±4.6, P=0.05). One month after surgery, 12 converted to sero-negative and 28 remained sero-positive. The patients who remained sero-positive revealed worse prognosis (P=0.02). Multivariate analysis revealed that postoperative s-p53 Abs was an independent risk factor for worse overall survival (adjusted hazard ratio=3.05, 95%IC=1.11–8.33, P=0.03). Conclusions: Perioperative monitoring of s-p53 Abs titers was useful to identify high risk group for tumor recurrence and a poor prognosis in esophageal carcinoma. Our clinical research for s-p53 Abs over a decade proved to be approved to use it as a biomarker for esophageal, colorectal and breast cancer by Japanese Ministry of Health and Welfare from Nov.1. 2007 No significant financial relationships to disclose.