A study of HER-2/neu expression and silver binding nucleolar organizer regions (Ag NORs) in perilesional normal salivary gland tissue

Salivary gland neoplasms comprise phenotypically and biologically diverse lesions of uncertain histogenesis.ObjectivesThe present study was carried out to assess the immunohistochemical expression of HER-2/neu protein and of silver binding nucleolar organizer regions in normal salivary tissue.Materials and methodsTwenty paraffin blocks of salivary tumors containing surrounding normal salivary tissue were used in the study. One section was processed to investigate HER-2/neu protein expression and another section was stained to assess the mean Ag NOR counts in normal salivary tissue.ResultsOnly two cases of the studied normal salivary tissue showed HER-2/neu expression (10%), which was expressed only in ductal cells with 4.2 ± 2.1 mean number of reactive cells per five high power fields (HPFs). Statistically significant (P = 0.01) higher mean Ag NOR counts in ductal (2 ± 0.83) than in acinar cells (1.2 ± 0.01) of normal salivary tissue were found.ConclusionIt was concluded from the data of the present study that ductal cells of normal salivary tissue are a proliferative pool and an oncogenic target which plays an important role in the histogenesis of salivary gland tumors.