The brains of SE or EE mice were compared for cell proliferation in tumour mass (as 5-bromo-2′-deoxyuridine (BrdU) incorporation), astrocyte activation at the tumour border (glial fibrillary acidic protein, GFAP+), M/Mφ infiltration (F4/80+) and activation of phagocytic activity (CD68+) within the tumour. This evidence concerns the gene CD68 and neoplasm.