Laviron et al.59 identified several TAM subpopulations in breast tumors that exhibit different ecological niches from those of macrophage subpopulations prior to tumor development and reported that the TAM composition shifts between proliferative and malignant neoplastic lesions; for example, the expression of CD11b is significantly elevated in malignant neoplastic lesion-associated enhanced green fluorescent protein (EGFP) cells compared with that in proliferative lesions, which is consistent with the CD11b phenotype of macrophages in the pretumor tissue epithelium. The gene discussed is ITGAM; the disease is breast neoplasm.