P53 is an independent prognostic factor for survival in thyroid cancer.

BACKGROUND p53 has been reported to be of prognostic importance in different types of cancer. Immunohistochemical measurement of p53 antigen activity could be a prognostic marker for aggressiveness and survival in thyroid cancer. Different types of antibodies have been used to detect p53 in previous studies without direct comparison to each other. PATIENTS AND METHODS A series of 54 patients with thyroid cancer who had undergone thyroidectomy between 1993 and 1998 is reported. All samples were chosen retrospectively and classified by routine histopathology, followed by immunohistopathological examination with three different types of antibodies (PAb1801, CM1 and DO-7) with the peroxidase method. Survival data was generated. RESULTS The mean time of follow-up was 9.0 years. Eighteen patients died. Twenty-three (42.6%) samples were positive for p53 using the antibody PAb1801, 17 (31.5%) with using CM1 and only 4 (7.4%) cases with DO-7. Statistical analysis determined that the size (p = 0.02) and classification of the tumor (p < 0.001), the age of the patients (p = 0.036), the presence of lymph node metastasis (p = 0.024) and positive staining for p53 (p < 0.001) were prognostic factors for overall survival by Kaplan-Meier method. Multivariate analysis revealed overexpression of p53 to be an independent significant prognostic factor of survival. CONCLUSION PAb1801 is the most sensitive antibody for detection of p53 protein in this type of cancer, and p53 is a prognostic factor for survival in thyroid cancer. This may provide further information for prognosis and aggressiveness of thyroid cancer.