FLOW CYTOMETRIC EXAMINATION OF P53 PROTEIN IN PRIMARY TUMORS AND METASTASES TO THE LIVER AND LYMPH-NODES OF COLORECTAL-CANCER

PURPOSE AND METHODS: To confirm prognostic significance of overexpress ion of p53 in cases of colorectal cancer, expression of p53 protein wa s examined by flow cytometry in 113 cases of colorectal cancer and its metastasis to the liver and lymph nodes. RESULTS: Overexpression of p 53 was found in 44 (39 percent) of the 113 primary tumors. There were no significant correlations among the level of p53 protein in the prim ary tumor, clinicopathologic features, and prognosis of colorectal can cer. Overexpression of p53 protein was detected in 72 percent (18/25) of liver metastases and in 40 percent (10/25) of lymph node metastases . Frequency of samples that mere positive for p53 was significantly hi gher for Liver metastases than for primary tumors and lymph node metas tases (P < 0.01). By comparing overexpression of p53 in primary tumors with that in corresponding secondary tumors, a decrease of more than 5 percent in the fluorescence index, compared with primary tumor, was not found in liver metastasis but was found in 20 percent of lymph nod e metastases. Incidence of cases with lower level expression of p53, c ompared with primary tumor, was significantly higher in lymph node met astases (32 percent) than in liver metastases (8 percent; P < 0.05). C ONCLUSIONS: From these results, it seems possible that overexpression of p53 may not be a good prognostic indicator of colorectal cancer and may be influenced by environments of the tumor.