الفهرس 
Oral Squamous Cell Carcinoma (OSCC)Only 14 pages are availabe for public view
 |  | from | 150 |  |  |
| | | from | 150 | | |
Abstract
OSCC is the most common oral malignant tumor. In the last 30 years, the 5-year survival rate of patients with OSCC has not improved despite advances in diagnostic techniques and improvements in treatment modalities. Indeed, the incidence and prevalence of OSCC are increasing, particularly in younger persons OVC is an uncommon rare low-grade variant of well differentiated OSCC, which accounts for 2-10% of all oral carcinomas. Loss of cellular adhesion has acritical role in tumorigenesis, as it serves to establish an intercellular cytoskeletal network for anchoring cells. It was proposed that there is an inverse relation between adhesion molecules integrity and tumor invasion. α-Catulin is an oncoprotein that helps sustain proliferation by preventing cellular senescence. α-Catulin also drives invasion and metastasis. It integrates the crosstalk between NF-kB and Rho signaling pathways increases the level of both α-catenin and β-catenin and therefore has potential effects on inflammation, apoptosis and also cytoskeletal reorganization. In addition, α-catulin was also shown to interact with dystrophin, which is a cytoplasmic protein that mediates cell–ECM adhesion by its anchorage to actin cytoskeleton. Thus, α-catulin may act as a cytoskeletal linker protein to modulate cell migration. ECM plays an important role in the maintenance of a suitable microenvironment for basic cell functions, such as cell adhesion, proliferation, and differentiation. The ECM functions not merely as a Chapter VII Summary and Conclusions 97 scaffold for migration but also as a signaling clue to regulate cell behavior through matricellular interactions. Interactions of malignant cells and stromal cells are indispensable for tumor growth and spread. This is referred to as tumor microenvironment; which develops in response to stimulation from the cancer cells and in turn has a profound impact on the progression of cancer. TSP-1 is a matricellular calcium binding protein that participates in cellular responses to growth factors, cytokines and it regulates cell proliferation, migration and apoptosis in a variety of physiological and pathological conditions. TSP-1 acts as a ligand for integrins which stimulate MMPs so promoting cancer cell invasion. TSP-1 stimulates cancer cell migration. However, the contribution of TSP-1 to oral carcinogenesis is not fully elucidated as evidenced by paucity of published studies in the current literature. This work was aimed to assess the relation of α-catulin and TSP-1 expression to biological behavior of OSCC and OVC. The present study included forty paraffin-embedded specimens divided into thirty cases of OSCC and ten cases of OVC obtained from the archives of Oral Pathology Department, Faculty of Dentistry, Tanta University after getting approval of the head of department. Paraffin-embedded specimens were routinely processed, stained with H&E and examined under light microscope for diagnosis and grading. IHC staining was also performed using anti-human α-catulin and TSP-1 antibodies for each case. Chapter VII Summary and Conclusions 98 Immunohistochemically, it was observed that α-catulin was upregulated with increased the grade of malignancy, i.e. poorly differentiated OSCC exhibited significantly higher α-catulin expression (p >0.05) as compared to moderately and well differentiated ones. Regarding TSP-1 expression in stromal cells, there was a significantly higher expression (p >0.05) in moderately differentiated OSCC in comparison to well differentiated ones. Moreover, there was a significantly higher expression (p >0.05) in poorly differentiated OSCC in relation to well differentiated ones. Non significant difference in TSP-1 expression was observed between well differentiated OSCC and OVC and also between moderately differentiated OSCC and poorly differentiated ones.