14567 Background: Because alternations of the p53 tumor suppressor gene are the most commonly observed and can occur early in the carcinogenic process, the accumulation of mutant p53 often leads to the production of p53 antibodies in the sera. The aim of this study is to evaluate the clinical usefullness as early detection marker and as a predictive biomarker of serum p53 antibodies in primary colorectal cancer. Methods: Serum samples are obtained before treatment and from time to time postoperatively and stored - 800C until assay. We employed the newly produced quantitative p53 antibodies ELISA Kit (MESACUP anti-p53 Test, MBL, Japan) to determine the presence of p53 antibodies in 311 patients with colorectal adenocarcinoma compared with the conventional two markers of CEA and CA19–9. Post operative clinical course and the long time survival were evaluated in sero-positive patients after resection. Results: The sensitivities of serum p53 antibodies, CEA and CA19–9 were 32.9%, 36.0% and 23.1%, almost equivalent to CEA and significantly higher than CA19–9. No obvious correlations were evident between the status of serum p53 antibodies and values of two markers, resulting in independent of the other markers. The sensitivity rate of CEA turned up as promotion of pathological stage, but the presence of serum p53 antibodies was more significantly associated with stage 0,I,II. One hundred-nine patients who showed preoperatively sero-positive patients were monitored for at least one year after resection. There was a significant correlation between operative curability and postoperative absence of serum p53 antibodies. Most of repeatedly positive patients treated as curative resection developed recurrence within one year in stageIIandIII. Repeatedly detected patients for serum p53 antibodies have a significantly poor prognosis compared with changed negative patients after curative resection in stageIIandIII. Conclusions: Serum p53 antibodies is easy and convenient, non- invasive, detectable many times and not necessary for surgical specimens for assay. Surveillance of p53 antibodies is rapid and readily facilitated test, which appears to be useful as a new tool for early diagnosis and as a postoperative predictive marker for colorectal cancer patients. No significant financial relationships to disclose.
Molecular detection of p16 promoter methylation in the serum of recurrent colorectal cancer patients
