Expression of ras oncogene p21 protein in early gastric carcinoma and adjacent gastric epithelia

Oncogenes are genes in human cells which, when activated, may be related to the development of cancer. They are sometimes activated as well during fetal development. Oncogenes, like other genes, contain the code which directs the production of specific proteins, and the ras family is one such group of proteins and oncogenes. Because the ras genes and proteins may be involved in the early stages of carcinogenesis, the levels of one of them, ras p21, has been measured in early gastric (stomach) cancers, in adjacent premalignant cells, and in normal gastric cells. Two types of gastric cancer have been postulated, an intestinal type and a diffuse or gastric type. Both types were examined in this study. Compared with normal cells, the levels of p21 were elevated in both types of early cancer cells and in adjacent premalignant cells with dysplasia (abnormal cell structure) associated with diffuse type but not intestinal type cancer. Interestingly, the levels of p21 were greater in premalignant cells than in cancerous cells, suggesting that p21 does not correlate with extent of cancerous changes. In fact, not all malignant cells contained p21. The data suggest that increased levels of ras p21 may be related to early events of gastric cancer development, but its continuous presence is probably not essential for maintenance of the cancerous cell. Also, the results indicate that the tests for the presence of p21 would not be useful as diagnostic markers for stomach cancer. (Consumer Summary produced by Reliance Medical Information, Inc.)