PECAM1 and renal cell carcinoma: Negative stainings were also observed for renal cell carcinoma (RCC) antigen, cytokeratin AE1/AE3, cytokeratin 7, high molecular weight cytokeratin (MA903), CAM5.2, CD1, CD31, CD117, S100, microphthalmia-associated transcription factor (MiTF), tyrosinase (DBA and AP), and desmin (only blood vessels were positive).