[Expression of protein p53: the marker of low neoplastic cell differentiation in thyroid carcinoma]

The aim of the study was to evaluate the frequency of positive staining of p53 protein in the course of thyroid carcinoma and to establish the prognostic value of such expression.

Immunohistochemical staining of frozen sections was performed in 159 patients with thyroid carcinoma (139 females and 29 males). The average age was 50.4 years. All patients have been followed-up for at least 5 years and the average time of observation was 10.7 years. There were 46% patients with papillary carcinoma, 39% with follicular carcinoma and 15% with poorly differentiated thyroid carcinoma in the study group. Additionally, staining was performed in 6 cases of anaplastic carcinoma. The expression of p53 protein was assessed by two-degree scale: a medium (10% of cells with positive staining) and strong (50% of positive staining).

In the group of 135 patients with well differentiated thyroid carcinoma the expression of p53 protein has been found in 55 cases (40.1%) but significantly more often in medium (69.1%) than in strong degree (30.9%). Significantly more often in expression has occurred among patients with poorly differentiated carcinoma (66%) and anaplastic carcinoma (100% of patients with strong expression in all cases). Comparing the frequency of p53 protein expression on every stage of disease, no significant difference has been found. The presence of p53 protein has not correlated with reduced changes in survival. In multivariate analyses the expression of p53 protein have not shown prognostic value.

The expression of p53 protein has concerned the poorly differentiated carcinomas of thyroid and has not correlated with the stage of disease. No influence of expression on clinical course of the well differentiated thyroid carcinoma has been found. Worse prognoses have correlated with poor differentiated thyroid cancer cases and with strong expression of p53 protein.