Expression of p53 and DR5 in normal and malignant tissues of colorectal cancer: correlation with advanced stages.

Apoptosis has to be drastically controlled in organs with important cell turnover such as the colon. Deregulation of this process is often present in tumor progression. Tissues of 82 patients treated for colorectal cancer (CRC) were analyzed using antibodies against AIF, p53, DR4, DR5, cleaved caspase-3 and the TUNEL method to detect apoptosis; whereas staining of Ki-67 was used as a proliferation marker. In situ immunohistochemical analyses were compared in non-tumor (NT) cells from normal adjacent mucous membranes with tumor (T) cells from patients with Stage I (n=6), Stage II (n=35), Stage III (n=27) and Stage IV (n=14) CRC. Results were correlated with the tumor stages and the treatment response of patients to improve the understanding of CRC development. p53 and DR5 expression decreased progressively with CRC stage, suggesting that these proteins are important markers of advanced tumor stages. Moreover, p53 appears as a prognostic factor to predict recurrence-free survival. Including the detection of p53 and DR5 for establishing the diagnosis of CRC and adapting the treatment to each patient is strongly suggested by our work.