Detection of the expression of P21, P53, P185 proteins and the mutation of ras, p53 genes in colorectal adenoma and carcinoma]

Expression of P21, P53, P185 proteins, mutations of ras, p53 genes in colorectal adenoma, carcinoma and transitional mucosa were studied using immunohistochemicstry and PCR-RFLP methods. The results showed that the positive rates of P21, P53 and P185 proteins in colorectal adenoma were 53.3%, 27.6% and 13.3% respectively, the expression of P21 and P53 were associated with the malignant potential of adenoma. The positive rates of P21, P53 and P185 proteins in colorectal carcinoma were 72.9%, 37.8% and 47.2% respectively. 9 adenomas and 40 carcinomas contained more than two protein expressions and their co-expression was associated with the malignant potential of adenoma and the prognosis of carcinoma. The mutation rates of ras gene in colorectal adenoma and carcinoma were 26.7% and 41.9% respectively. The ras gene mutation was associated with the malignant potential of adenoma. The mutation rates of p53 gene (codon 248) in adenoma and carcinoma were 3.3% and 14.9% respectively. The prognosis of patients having gene mutation of both ras and p53 were poor. The results suggested that the alterations of ras, p53 and c-erbB-2 genes are involved in the tumorigenesis and development of colorectal carcinoma.