In this study, the investigators aim at:

1. Evaluate the presence of vasculogenic mimicry in urothelial carcinomas by CD31-PAS double staining.
2. Correlate the presence of vasculogenic mimicry with the clinicopathologic features as age, sex, TNM stage, pathological grade, recurrence, carcinoma in situ, lymphovascular emboli, lymph node metastasis, necrosis, surgical margin, multifocality and tumor size in urothelial carcinoma.

Bladder cancer is the ninth most common cancer worldwide which seriously affects human health. In Egypt, it is the third common malignant tumor.

Urothelial carcinoma (UC) is considered the most common histologic type of bladder cancer.

It is well recognized that the biological behavior of several cancers is closely related to their blood supply. Tumor progression and metastasis have been long associated with tumor angiogenesis. However, several studies demonstrated that vascular targeting drugs which induce endothelial cell apoptosis have a little effect. So, it has been suggested that novel tumor microcirculation patterns may exist in these neoplasms.

Vasculogenic mimicry (VM), is a novel tumor microcirculation system. Maniotis et al initially discovered VM in melanoma and defined these channels to be composed of tumor basement membrane lined externally by tumor cells, lacking blood vessel endothelium and containing plasma and red blood cells. So VM can be distinguished using immunohistochemical (IHC) staining and histochemical double staining. VM is CD31- or CD34-negative (endothelial markers) and periodic acid-Schiff (PAS) positive.

Vasculogenic mimicry was detected in several malignant tumors. Several studies reported that VM can promote tumor progression and metastasis and it is positively associated with pathological grade, stage, recurrence and drug resistance. Previous studies which evaluate, the role of VM in urothelial carcinoma yield controversial results. So, the value of VM in urothelial carcinomas and its relation to the clinicopathologic parameters remains to be elucidated.

Inclusion Criteria:

• - Specimens of urothelial carcinoma.

Exclusion Criteria:

• - Any criteria that not fulfill the inclusion criteria such as resected urinary bladder tumors other than urothelial carcinoma.

The study will be conducted using formalin fixed paraffin embedded blocks of sixty cases of urothelial carcinomas . These blocks will be obtained from laboratory archives of the Pathology Department, Assiut University Hospital, Faculty of Medicine. Clinical data for this study will be obtained from laboratory archives of the pathology department, Assiut University Hospital, Assiut University.