AIF1 and neoplasm: To test whether the local proliferation of monocytes, macrophages and microglia contributes to their increased accumulation in PVA, we performed a BrdU incorporation experiment with two pulses every 6 hours (at 10 mg/kg body weight) for 12 hours before sacrificing tumor-bearing animals of the three genotypes and quantifying Iba1+BrdU+ cell numbers.