Renal cell carcinoma (RCC) is the most frequently occurring primary renal neoplasm. There are several histological variants of RCC that are associated with variable prognostic outcomes. Epithelial-mesenchymal transition (EMT) is a phenomenon in which the epithelial cells acquire some mesenchymal criteria as enhanced invasive potential. There are several cell surface molecules that are implicated in EMT. Moesin is one of these molecules that is involved in EMT, which is associated with enhanced invasive potential and poor prognosis. Targeting Moesin by novel therapeutic agents may prevent EMT and improve prognosis of patients with RCC.

Inclusion Criteria:

1. All cases of ccRCC.
2. Tissue blocks with material adequate for immunohistochemical evaluation.
3. All cases with accessible clinical data.

Exclusion Criteria:

1. Cases of renal neoplasms other than ccRCC.
2. Patients who received preoperative chemotherapy or radiotherapy.
3. Patients with ccRCC who were diagnosed by tru-cut biopsies only and didn't undergo radical operations.
4. Cases with insufficient/destructed material.
5. Patients with inadequate clinical data.

The present work will be performed on archived formalin-fixed, paraffin-embedded renal cell carcinoma tissue blocks that were belonged to 55 patients who were admitted to Sohag University Hospital because of loin/ back pain, from January 1st,2017 to December 31st, 2021. Radiological evaluation revealed renal neoplasms and patients underwent radical nephrectomies.