Normalization of Serum p53 Antibody Levels in Patients after Curative Resection for Colorectal Cancer

Background: The aim of this study was to evaluate the significance of high serum p53 antibody (p53Ab) levels in relation to curative resection of colorectal cancer. Patients and Methods: Between 2007 and 2010, 24 patients with colorectal cancer with higher-than-normal preoperative serum p53Ab, measured by enzyme-linked immunosorbent assay, were enrolled in this study. After curative resection, their serum p53Ab and carcinoembryonic antigen (CEA) levels were measured at one, six, 12, 18, and 24 months after surgery. The relationship between clinicopathological features and the presence of serum p53Ab was evaluated. Results: None of the patients developed recurrence up to 24 months after the surgery. The positive rate for CEA was 33.3% before surgery, 16.7% at one month after surgery, and 0% at six months and more, while the rate for p53Ab was 75% at six months, 70.8% at 12 months, 58.3% at 18 months, and 54.2% at 24 months after surgery. The positive rate for serum p53Ab at 24 months after the surgery correlated with the one before and that at one month after the surgery. Conclusion: For patients with colorectal cancer and high preoperative serum p53Ab levels, serum p53Ab does not seem to be a useful marker of recurrence after curative resection, since normalization of serum p53Ab levels requires years after surgery. The expression of the p53 protein has been reported in a number of human tumor types, including those of breast, lung, esophagus, stomach, and colorectum (1-6). p53 protein is detectable by immunohistochemical staining, and the overexpression of mutant p53 protein has been found to induce serum p53 antibody (serum p53Ab) in 30-48% of patients with esophageal carcinomas (7-12). Serum p53Ab as a serological marker of cancer has been recently gaining attention. In patients with esophageal carcinoma, the presence of p53Ab in the serum has been reported to be assosiated with poor prognosis, low histological grade, and high incidence of lymph node metastasis (13-15). On the other hand, in patients with colorectal carcinomas, little is known about the correlation between serum p53Ab and clinicopathological features of colorectal cancer. This study was undertaken to evaluate the significance of high p53Ab levels in serum, in relation to curative resection of colorectal cancer.