Detection of C-KIT (CD117) molecule in benign and malignant salivary gland tumours

C-KIT (CD117), a tyrosine kinase receptor, is involved in the growth and development of normal tissues and some types of neoplasms. In the present study we analysed the expression of this molecule in salivary gland tumours. Archival formalin-fixed, paraffin-embedded sections of 40 benign and 57 malignant salivary gland tumours were retrieved and retrospectively studied immunohistochemically using a polyclonal C-KIT antibody in an Envision/HRP technique. In addition five samples of chronic submandibular sialadenitis, five normal minor salivary glands and parotid or submandibular gland tissue adjacent to benign tumour were also studied. C-KIT expression was observed in cases of adenoid cystic, acinic cell polymorphous low grade, epithelial-myoepithelial, carcinosarcoma and basal cell adenocarcinomas, as in luminal cells of pleomorphic adenomas, in serous acinar and only in intercalated and a small number of striated ductal cells of inflammatory salivary gland tissue, whereas normal salivary lobules were generally negative except a weak positivity of intercalated cells. Contrary to other reports, this study suggests that, C-KIT protein does not appear to be an exclusively specific marker for benign or malignant salivary gland neoplasms, but may be useful in differential diagnosis of adenoid cystic carcinoma from polymorphous low grade adenocarcinoma. Furthermore its expression in serous acinar cells in sialadenitis and intercalated ductal cells in normal and inflammatory lesions may indicate a possible participation in pathogenesis of both neoplastic and non-neoplastic salivary gland diseases.