[Expression and significance of oncoprotein p53, rasp21 and p185 in carcinomas and polyps of the large intestine].

Seventy eight cases of carcinoma and 14 cases of poly of large intestine were examined to observe the expression of p53, rasp21 and p185 oncoproteins with immunogold silver staining method. The positive expressions for p53, rasp21 and p185 were 53.9%, 46.2% and 51.3% respectively. But only poorly positive expression was found in large intestine polyps for p185 staining. The difference between the carcinomas and polyps for p185 staining was significant (P < 0.01). The normal mucoepithelium near the cancer region expressed positive staining for p53, rasp21 and p185 were 0%, 2.6% and 5.1% respectively. These results were also significantly different when compared to cancer tissue (P < 0.01). In addition, of these 78 cases, 33 cases (42.3%) gave coordinately positive expression for p53 and rasp21 oncoprotein; p53 positive expression was obviously stronger in poorly differentiated carcinoma and mucoadenocarcinoma than in highly and moderately differentiated adenocarcinoma (P < 0.01).