The Incidence of mTOR Marker in Tracheal Adenoid Cystic Carcinoma by Immunohistochemical Staining

Introduction: There is an association between the activation of mammalian target of rapamycin (mTOR) signaling and aggressive tumor growth in multiple forms of cancer,including adenoid cystic carcinoma (ACC). ACCs are uncommon yet a malignant form of neoplasms that arises within the secretory glands. Therefore, the aim of this study was to investigate the increase of mTOR in the ACC tumors in order to survey the possibility of treating these tumors with mTOR inhibitors. Material and methods: Samples from known cases of the lung and tracheal ACC were retrievedfrom the archives of the pa-thology department of Masih Daneshvari hospital, and immunohistochemical (IHC) staining for mTOR was performed on them. After preparation of the blocks with specific antibodies, tumor cells with cytoplasmic and/or nuclear expression of mTOR were considered as positive cells by applying a specific scoring method introduced in this study. Results: The paraffin blocks of 26 patients were surveyed and the IHC marker of mTOR was positive in the tumors of 10 patients (38.5%). Out of 10 mTOR positive cases, 5 were females and 5 were males. The primary site of the surveyed tumors was the trachea and bronchus in 12 cases (46%), salivary glands in 7 individuals (27%), and lung tissue in 7 cases (27%), and there was no significant correlation between the primary site of the ACC tumors and the existence of the mTOR markers in them (P = 0.67). From all cases, 13 patients (50%) had cribriform and tubular cells without solid components, 9 cases (34.6%) had cribriform and tubular with less than 30% of solid components, and 4 cases (15.4%) had cribriform and tubular cells with more than 30% of solid com-ponents. There was no significant difference between the morphologies and the existence of mTOR markers in them (P = 0.741). Conclusions: As the incidence of mTOR markers is seen in patients with tracheal ACC, evaluation and scoring of mTOR in these persons can be helpful as further studies can distinguish the use of it in the treatment of the disease.