Differences in expression of oncogenes and tumor suppressor genes in different sites of head and neck squamous cell

Background: In most studies concerning chromosomal changes or protein expre ssion in head and neck squamous cell carcinomas (HNSCC) no distinction is m ade between the sites within this area. The behaviour of tumors arising in one site or the other, however, differs significantly, suggesting different intrinsic tumor properties. In this study we compared the expression of se veral proteins (p53, Rb, cyclin D1 myc, bcl-2, EGFR, neu, E-Cadherin, Ep-CA M, Desmoplakin1 and nm23) in the three major sites of HNSCC (larynx, pharyn x, and oral cavity). Materials and methods: Expression of the proteins was studied by immunohistochemistry in 33 laryngeal, 31 pharyngeal and 36 oral carcinomas. Results: Cyclin D1 had a very high level of expression in the p harynx (p = 0.0004) and EGFR very low in the larynx (p < 0.0001) compared t o the other sites. To a lesser degree p53 (p = 0.05), Desmoplakin1 (p = 0.0 4) and Ep-CAM (p = 0.02) showed statistically nearly significant difference s. For the other proteins no statistically significant difference in expres sion was found. Conclusion: These results show that the expression of a num ber of proteins is not identical in the three major localisations of HNSCC and indicate the different tumor biology of cancers originating from differ ent sites in the Head and Neck. It is therefore not justified to consider t he different localisations as one entity. Moreover, these differences may h ave clinical and prognostic relevance.