Anti-CD68 marks cells of the monocyte/macrophage lineage. This antibody is able to stain monocytes, Kupffer cells, osteoclasts, granulocytes and their precursors; lymphomas are negative or show few granules. This antibody can be useful for the identification of myelomonocytic and histiocytic tumors. Since it recognizes a formalin-resistant epitope possibly associated with lysosomal granules, other lysosome-rich cells can also be stained. It is often tested together with AACT and lysozyme to improve diagnostic accuracy.