Expression of ras p21 in benign and malignant thyroid lesions.

It is now widely accepted that human neoplasms arise as a result of a sequence of mutations affecting the structure of genes involved in growth control. Identifying the nature of such genetic mutations in thyroid neoplasms and their prevalence in the various tumor phenotypes is critical to the understanding of their pathogenesis. Mutational activation of ras oncogenes has been associated with human thyroid neoplasia. We examined the expression of ras oncogene in benign hyperplastic or inflamatory lesions of the goiter, as well as in benign and malignant thyroid tumors. Although no significant differences of ras oncogene expression was found between benign and malignant lesions, the overexpression in proliferative areas generally suggests the possible involvement of ras oncogene in the trophic hormone control of the thyroid.