Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Oral and Maxillofacial Surgery

Evaluate the immunohistochemical expression of EpCAM in different grades of MEC and solid variant of adenoid cystic carcinoma (solid AdCC) in comparison with the normal salivary glands, to ascertain the possible prognostic significance and propose EpCAM targeted therapy as a possible treatment approach for patients with salivary gland tumors overexpressing this cell surface marker.Material and Methods: A total of 60 archival paraffin embedded specimens (12 normal salivary gland tissue, 36 MEC and 12 Solid AdCC) were collected and EpCAM expression was evaluated by immunohistochemistry. The total immunoscore (TIS) was evaluated, which represented the product of the proportion score (PS) and the intensity score (IS). The term {u2018}EpCAM overexpression{u2019} was given for tissues showing a total immunostaining score >4. Results: A highly significant difference was detected between TIS percent values in control, different grades of MEC and solid AdCC. In MEC, EpCAM expression increased in HG-MEC compared to IMG-MEC and LG-MEC (Pearson's chi square test, p < 0.01), but no significant difference was observed between LG-MEC and IMG-MEC (Pearson's chi square test, P> 0.05). Solid AdCC showed the highest TIS percent values in relation to different grades of MEC. HG-MEC and solid AdCC were found to be the highest EpCAM expressors (TIS>4). Although, lack of EpCAM expression was detected in 2 cases (16.7%) of HG-MEC and one case (8.3%) of solid AdCC. Conclusion: EpCAM was frequently detected in MEC and solid AdCC making these tumours potential targets for anti-EpCAM therapies

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