CD68 and renal cell carcinoma: CD68: Cluster of differentiation 68; CKAE1/3: Cytokeratin AE1/AE3; GFAP: Glial fibrillary acidic protein; GMS: Grocott methenamine silver; NeuN: Neuronal nuclei; SALL4: Spalt-like transcription factor 4; CCRCC: Clear cell renal cell carcinoma