Figure 4From: Primary osteosarcoma of the urinary bladder following cyclophosphamide therapy for systemic lupus erythematosus: a case report Immunohistochemistry. a) Neoplastic cells do not express cytokeratins. Normal urothelium constitutes the positive intrinsic control of the stain (Primary anti-pancytokeratin Ab, ABC × 100). b) Diffuse and strong p53 positivity by the neoplasm (Primary anti-p53 Ab, ABC × 200).Back to article page