الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 352 |  |  |
| | | from | 352 | | |
Abstract
Salivary gland tumors are a diagnostic challenge due to their complex histopathological features and considerable variation with regard to clinical characteristics, biology, and clinical behaviour. The cancer stem cell marker of c-kit is a member of the transmembrane receptor tyrosine kinase family. After its activation, a signalling cascade begins that contributes to the regulation of cell proliferation. Moreover, the proto-oncogene of c-kit can induce EMT,which has been proposed as an essential early step in tumor metastasis and progression. Epithelial-mesenchymal transition is also known to disrupt cell–cell contact as tight junctions disband. Claudin-1 is a member of the tight junction protein. Dysregulation of Cld-1 plays a central role to the cellular transformation and acquisition of metastatic potential. Metastatic dissemination through the lymphatic system represents one of the major routes through which neoplastic cells may reach distant organs. Podoplanin is a specific marker for lymphatic endothelial cells and lymphangiogenesis in tumors.Therefore, the current work aimed to evaluate the mmunohistochemical expression of cancer stem cell markers: (c-kit), tight cell- cell junction protein (Cld-1) and asses the density of lymph vessels by using (PDPN) antibody among MSGTs, in relation of these markers to the clinicopathologic factors as well as prognostic microscopic parameters.The present study was conducted on archival paraffin blocks of 20 cases of AdCC, 11 cases of MEC, 10 cases of CXPA, six cases of AcCC, and three cases of PAC.The retrieved paraffin blocks were employed to prepare four microns paraffin sections to conduct the following techniques:1- Haematoxylin and eosin staining to confirm diagnosis based on the WHO classification of salivary gland tumor (2017)and Cld-1 among the studied MSGTs in relation to all probable prognostic microscopic characteristics except tumor necrosis. The immunopositivity for PDPN was detected among endothelial cells lining lymphatic vessels but not blood vessels. Moreover, only malignant myoepithelial cells reacted to PDPN. High grade MEC showed the highest mean value of LMVD among all cases of the current MSGTs, while AcCCs revealed the lowest mean.