Background: In clinical practice it became clear that conventional prognostic parameters of oral squamous cell carcinomas (OSCC) are of limited value for the prediction of a disease-free survival. The overexpression of erbB oncogenes is of importance for the clinical course of a variety of solid tumors. After discovering amplifications of erbB oncogenes even in OSCC, it was the aim of the present study to clarify the potential of oncogenes as additional prognostic markers.
Materials and methods: The amplification of the erbB oncogenes in tumorous tissue of 85 OSCC patients was determined using the double-differential polymerase chain reaction. Histologically healthy mucosa in these patients was also studied. In univariate analysis the amplification of erbB oncogenes with clinical and histopathological prognostic parameters was compared.
Results: No significant correlation between common prognostic parameters and erbB-2 amplification was found. Patients whose OSCC tissue showed an average gene copy number for erbB-2 of greater than 1.2, for erbB-3 below 0.11, and a ratio of erbB-1 and erbB-2 below 0.31 had a statistically significant decrease in disease-free survival. Even in histologically healthy oral mucosa from tumor patients an amplification of erbB oncogenes was found.
Conclusions: ErbB oncogene amplifications in oral squamous cell carcinomas play a significant role as a prognostic factor and seem to be effective in predicting decrease in disease-free survival. Genetic abnormalities in tumor-surrounding tissue support the field cancerization hypothesis.