OVEREXPRESSION OF P53 IN TALL CELL VARIANTS OF PAPILLARY THYROID-CARCINOMA

Background. The tall cell variant (TCV) is a clinically aggressive sub type of papillary thyroid cancer. The aim of this study was to discove r the prevalence of mutant forms of p53 protein in this subtype and re late it to clinical outcome. Methods. Eighteen patients with TCV and a control group with common papillary cancers, matched for age and gend er, were studied. The p53 mutations were identified by means of immuno histochemical staining. Data reviewed were overall survival, recurrenc e, TNM stage, and p53 positivity. Results. p53 mutations occurred in 1 1 (61%) patients with TCV compared with two (11%) in control group (p = 0.05). In the TCV group two patients died of the disease (11%) and e ight (44%) had local recurrences of distant metastases compared with n one in the control group. All deaths and 70% of the recurrences occurr ed in patients with stage III or IV disease. p53 positivity did not co rrelate with any reduction in survival (7% compared with 9%) but with increased rate of local (23% compared with 4%) and distant (23% compar ed with 13%) recurrences. Conclusions. TCV was associated with a signi ficantly higher rate of p53 positivity than common papillary carcinoma . The stage of the disease seemed to be a better prognostic indicator than p53 positivity for overall survival.