Using immunofluorescence staining of PyMT tumors for CSF-1R, macrophages (CD68+/CD206+/CD31−), and endothelial cells (CD31+) as described previously, we found that greater than 90% of all CD68+ macrophages throughout the tumor tissue co-express CSF-1R and 97% of CD68+/CD206+ TMEM doorway macrophages (identified by simultaneous contact with tumor cells and endothelial cells and co-expression of CD68 and CD206 without CD31 expression) also express CSF-1R (Fig. 2C, D). The gene discussed is PECAM1; the disease is neoplasm.