Implications of CEA and p53 overexpression in the poor prognosis of colorectal cancer.

Colorectal cancer (CRC) is one of the most frequent and aggressive types of cancer. Several clinicopathologic features have been studied to identify the prognostic factors that can provide information concerning the favorable or the poor outcome of colorectal cancer. In the present study, the relationship between serum CEA, p53 expression, and DNA index to the different clinicopathological characteristics of colorectal cancer patients was sought. Fifty patients with CRC were included in this study. p53 protein was detected immunohistochemically using specific monoclonal antibodies. Samples were investigated for DNA index using flow cytometry. In addition, the serum CEA was determined using ELISA. The results showed that 27/50 (54%) were positive for p53. Concerning CEA reactivity, it was found that 35/50 (70%) were reactive for CEA. These results indicate that CEA is more sensitive than p53 to detect colorectal cancer. There was a statistically significant difference between the recurrent and nonrecurrent groups in the CRC Duke's stages, survival time, serum CEA (p = 0.001, 0.016, < 0.001, respectively). Kaplan-Meier method and log-rank test showed that the mean survival time for cases positive for both p53 and CEA is significantly different from cases positive for CEA only, positive for p53 only, and negative for both p53 and CEA (p = 0.0002). Survival time was statistically significant with respect to sex, p53, CEA, and Duke's stages (p = 0.006, 0.024, 0.001, 0.017, respectively). Cox regression model showed that the prognosis of colorectal cancer is influenced by sex, p53, CEA reactivity, and CRC Duke's stages (p = 0.014, 0.006, 0.019, 0.014, respectively). In conclusion, the use of more than one tumor marker may successfully aid in the prediction of colorectal cancer prognosis.