Expression of translation initiation factor eIF-2alpha is increased in benign and malignant melanocytic and colonic epithelial neoplasms.

BACKGROUND: Stimulation of resting cells by growth factors leads to an increase in the rate of protein synthesis, which is necessary for cell growth and division. Translation initiation factor eIF-2alpha is one of the key translation factors mediating the effects of growth factors on protein synthesis. In normal cells, expression of eIF-2alpha is increased transiently, but its levels are elevated constitutively in oncogene-transformed cells. Overexpression of constitutively active eIF-2alpha in rodent cells makes them tumorigenic. In this article, the authors report their findings on the increased expression of eIF-2alpha in human benign and malignant neoplasms originating from melanocytes and colonic epithelium.
METHODS: Immunohistochemistry was used to analyze the expression of eIF-2alpha, eIF-4E, and cyclin D1 in melanocytic nevi and melanomas and the expression of eIF-2alpha in colonic adenomas and carcinomas.
RESULTS: The authors found that the expression of eIF-2alpha was increased markedly in both benign and malignant neoplasms of melanocytes and colonic epithelium.
CONCLUSIONS: Increased expression of eIF-2alpha took place in both benign and malignant neoplasms of melanocytes and colonic epithelium. These findings suggest that elevated expression of this translation initiation factor may contribute to tumor initiation and progression but that it is not sufficient for establishing a malignant phenotype in the tumors analyzed in this study. Copyright 2003 American Cancer Society.