DEMONSTRATION OF C-ERBB-2 ONCOGENE OVEREXPRESSION IN SALIVARY-GLAND NEOPLASMS BY IN-SITU HYBRIDIZATION

The level of c-erbB-2 cellular mRNA in 18 salivary gland tumours and i n 7 normal salivary glands was determined by in situ hybridization usi ng [S-35] labelled RNA probes. Computer assisted quantitation of the a utoradiographic signal indicated a significantly higher c-erbB-2 expre ssion in the tumour group (22.64 grains per cell +/- 3.79; 95% CI) as compared to the non-neoplastic salivary gland tissue (4.11 +/- 0.90; 9 5% CI). The c-erbB-2 expression as measured by grain counts per cell f or the pleomorphic adenomas (16.29 +/- 1.87; 95% CI), mucoepidermoid c arcinomas (31.52 +/- 0.08; 95% CI) and the acinic cell carcinomas (44. 24 +/- 17.11; 95% CI) were significantly greater than the expression f or the normal group. The acinic cell carcinomas exhibited the greatest level of expression. As observed at the individual cell level, the au toradiographic signal was distributed uniformly in the neoplastic tiss ues, regardless of the cell type. This study confirms the hypothesis t hat the c-erbB-2 oncogene is overexpressed at the mRNA level in saliva ry gland tumours.