Immunohistochemical analysis of p53 in colorectal cancer regarding clinicopathological correlation and prognostic significance

The overexpression of the tumor suppressor gene p53 was investigated immunohistochemically in 144 cases of primary colorectal cancer and in 8 cases with cancer in the corresponding metastatic lymph nodes. Abnormalities in p53 expression were found in 36 cases (25%) of the 144 primary cancer cases. In addition, p53-positive tumors were found to metastasize frequently to the lymph nodes, as compared to p53-negative tumors (61.1% vs. 41.7%, P = 0.0428). p53 staining was identical in 7 of 8 (87.5%) cases in primary and metastatic lesions. When the DNA content of the tumor was determined by flow cytometry, the DNA index (mean +/- SD) was significantly higher in p53-positive tumors than in p53-negative tumors (1.57 +/- 0.38 vs. 1.39 +/- 0.37, P = 0.012). Therefore, the immunohistochemical data of p53 in colorectal cancer may help in potentially predicting metastatic spread to the lymph nodes.