Fig. 2
From: Early immunohistochemical detection of pulmonary micrometastases in dogs with osteosarcoma
a Section of lung tissue from a dog with osteosarcoma without macroscopic metastases (case 9) showing immunolabeling (red staining) with tumour protein-3 (TP-3) of a pulmonary micrometastasis (defined as a cluster of 5–50 TP-3 positive cells). The micrometastasis is lodged within a pulmonary arteriole. b Section of the same tissue as in a, but without TP-3 antibody (negative control). Snap frozen tissue, immunoperoxidase stain, TP-3, AEC chromogen and haematoxylin counterstain, 200 × magnification