Proliferative (MIB1, mdm2) Versus Anti-Proliferative (p53) Markers in Head and Neck Cancer. An Immunohistochemical Study

József PIFFKO1, Ágnes BÁNKFALVI2, Dietmar ÖFNER3, Martin TÖTSCH4, Axel BERENS1, Ulrich JOOS1, Werner BÖCKER2, Kurt Werner SCHMID2

1Department of Maxillo-Facial Surgery, University of Münster, Münster, Germany
2Department of Pathology, University of Münster, Münster, Germany
3Deparment of Surgery, University of Innsbruck, Innsbruck, Austria
4Department of Pathology, University of Innsbruck, Innsbruck, Austria


Formalin fixed and paraffin embedded samples from 36 squamous cell carcinomas of the larynx and the oral cavity (pT2N0M0, R0) surrounded by non-tumorous mucosa were studied immunohistochemically using a panel of four different anti-p53 antibodies (CM1, PAb1801, D07, PAb240), a monoclonal anti-mdm2 antibody and MIB1, following wet autoclave antigen retrieval. P53 immunoreactivity was detected in 11/14 laryngeal and in 9/22 oral carcinomas. All p53 positive oral, and all but one laryngeal tumors revealed mdm2 positivity as well, whereas in p53 negative tumors 4/12 and 1/3 mdm2 immunopositive cases were demonstrated, respectively. MIB1 labeling indices of the tumors ranged between 18% - 64% in p53 positive cases, and 10% - 53% in p53 negative ones. The difference was not statistically significant. Close spatial coexpression of p53, mdm2 and MIB1 immunoreactivity was observed at the invasive front of the carcinomas and in the basal and suprabasal layers of the non-tumorous epithelium in all p53 positive cases. However, the MIB1 expression was similarly increased at the invasive margins in carcinomas lacking immunohistochemically detectable p53 alterations. Our results strongly suggest that p53 overexpression does not necessarily correspond to increased rate of proliferation, but rather to mdm2 overexpression and is largely dependent on the anatomical site in case of small and localized squamous cell carcinomas of the head and neck region. Pathology & Oncology Research, Vol 2, Nr 1, 37-42, 1996

Key words: p53; mdm2; MIB1; immunohistochemistry; wet autoclave pretreatment; head and neck cancer

Received: Jan 12, 1996; accepted: Feb 20, 1996
Correspondence: Kurt Werner SCHMID, Department of Pathology, University of Münster, Domagkstrasse 17 Münster D-48149, Germany; Tel: (49)(251)835484, Fax: (49)(251)835460

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