FIELD CANCERIZATION IN SALIVARY TISSUE: AN IMMUNOHISTOCHEMICAL STUDY OF Mdm2 AND Bcl-2 IN HISTOLOGICALLY NORMAL TISSUE ADJACENT TO SALIVARY TUMORS

The present study was carried-out to investigate the concept of field cancerization in salivary tissue by an immunohistochemical detection of Mdm2 and Bcl-2 oncoproteins in histologically normal tissue adjacent to salivary tumors. Sections from 18 archival paraffin blocks of salivary gland carcinomas were processed to demonstrate the immunohistochemical expression of Mdm2 and Bcl-2 oncoproteins in peritumoral normal salivary tissue. Eight cases (44.4%) showed Mdm2 expression and another four cases (22.2%) showed Bcl-2 reactivity. A perfect positive correlation (R=0.98) between Mdm2 and Bcl-2 expression in normal salivary tissue around salivary tumors was reported in the present study. The findings of the present work suggests that, although the studied peritumoral salivary tissue appeared histologically normal, it revealed an immunohistochemical expression of anti-apoptotic oncoproteins which may signal the tumorigenesis of this tissue. These oncoproteins may be useful in the early detection, risk assessment, disease monitoring and chemoprevention of salivary gland tumors.