Ras P21 Level and Tyrosine Kinase Activity during Carcinogenesis of Human Colon Tumors
The relationship between ras oncogene expression, clinical staging and fraction of S-phase cells has been studied in 25 colon adenomas and 42 colon carcinomas by quantitative immunohisto chemistry. The level of tyrosine kinase activity in 27 colon carcinomas has also been evaluated. Elevated level of ras p21 could be detected in the hyperplastic and dysplastic lesions, in 32% of colon adenomas and 52% of colon carcinomas. A strong correlation could be found between the high rate of cell proliferation and the increased level of ras p21 both in adenomas and carcinomas (r1 = 0.8418; r2 = 0.9007). There was no correlation between clinical stages and p21 content of colon carcinomas (p = 0.49). A high level of tyrosine kinase activity was found in 26% of colon carcinomas and a close correlation between the level of tyrosine kinase activity and the high ration of S-phase cells has been demonstrated. Our results have shown that the mitotic signal transduction in 52% of colon carcinomas is mediated by ras p21 protein. Elevated level of tyrosine kinase activity in 26% of colon carcinomas suggests the participation of growth factor receptors and/or oncogenes homologous with these receptors in the signal transduction pathway.
KeywordsColon Carcinoma Colon Adenoma Human Colon Tumor Normal Colonic Epithelium Intact Epithelium
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