RAS AND p53 EXPRESSION IN HUMAN THYROID CARCINOMA

Both benign and malignant nodular disorder of the thyroid gland may give rise to similar symptomatology. Even though clinical background and pathologic criteria may predict prognosis, there are still patients without these adverse prognosis indicators who develop subsequent local invasion or distant metastasis after surgical intervention and eventually succumb to the disease.1] In recent years it has become apparent that malignant transformation is a result of the accumulation of genetic abno…

Ras and p53 expression in human thyroid carcinoma

Objective: To investigate the possible interaction between the ras and p53 genes over-expression in thyroid carcinoma, and whether there is a correlation between the ras and p53 over-expression and clinicopathological criteria. Methods: Eighty patients with thyroid lesions were examined for expression of ras and p53 genes by the labeled streptavidin biotin peroxidase (LSAB) method. Of these patients, 54 were diagnosed (average age: 39.9(15.9 years) with malignant lesions. Of those included in the study, 31 has papillary carcinoma, 13 had follicular carcinoma, 7 had medullary carcinoma, 3 had undifferentiated carcinoma and 19 were stratified to stage I, 28 to stage II, 2 to stage III and 5 to stage IV according to TNM staging system. Twenty-six benign nodular thyroid disorders were studied as control. Results: Positive immunostain results for ras and p53 genes were statistically significant between thyroid carcinomas and benign disorders (90.7% vs 23%, 55.5% vs 30.7%, P<0.05). Both p53 and ras overexpressions coexisted in 30 thyroid carcinomas, and of these, 3 died and 5 had recurrences within 4 years. Conclusions: Activation of ras gene and inactivation of p53 gene were cooperatively associated in thyroid tumorigenesis. The concurrent overexpressions of ras and p53 could result in a poor prognosis.