CD68 is expressed in cytoplasmic granules in macrophages, histiocytes myocytes, giant cells, Kupffer cells, and osteoclasts. CD68 is often used as a pan-macrophage marker for analysis of tumor-associated macrophages in cancer samples, but is expressed by some cancers including renal cell carcinoma. CD68 is expressed in cytoplasmic granules in macrophages, histiocytes myocytes, giant cells, Kupffer cells, and osteoclasts. CD68 is often used as a pan-macrophage marker for analysis of tumor-associated macrophages in cancer samples, but is expressed by some cancers including renal cell carcinoma.