P53 overexpression in epidermoid carcinoma of the head and neck

Angela Flavia Logullo, Luiz Paulo Kowalski, Sueli Nonogaki, Roberto E. V. Miguel, Humberto Torloni, Ricardo R. Brentani

The theory of field cancerization in tumors of the head and neck reflects the complex oncogenesis that occurs in this region. The mechanisms that control cell proliferation at the molecular level in epidermoid carcinomas (ECs) of the upper aerodigestive tract are still unclear. Mutations in p53 are the genetic alterations most often detected in ECs of the head and neck and seem to contribute actively to the carcinogenic process triggered by p53 as a tumor-suppressor gene and to its association with tobacco. The objective of the present study was to investigate the expression of p53 protein in epidermoid head and neck carcinomas by immunohistochemistry and its immunohistochemical correlation with other prognostic factors. The study was conducted on 63 consecutive ECs cases not submitted to previous treatment. Specimens of the tumor and of the normal adjacent mucosa were collected during surgery and submitted to immunohistochemical reaction for the determination of the expression of anti-protein p53 antibody (M7001 DAKO A/S, Denmark). Anatomo-clinical and demographic data were not significantly correlated with the presence of lymph node metastases or p53 expression in the tumor or in the adjacent normal mucosa. Tumor localization in the larynx was significantly correlated with p53 expression. Histological grading as grades I, II, III and IV was correlated with significant p53 expression (p = 0.025). 1) in the studied material obtained from 63 cases of head and neck ECs, we detected a 48 percent rate of immunohistochemically detectable p53 overexpression; 2) we did not detect a relationship between demographic patient data and p53 expression in the tumor or in the normal adjacent mucosa; 3) p53 overexpression was significantly more frequent in ECs material from the larynx: and 4) The presence of 12 cases with p53 overexpression in the normal adjacent mucosa and with a p53-negative tumor is in agreement with the theory of field cancerization. Follow-up of this patient series for a longer period of time will permit a better analysis of these values.