Proportion of infiltrating IgG-binding immune cells predict for tumour hypoxia

Macrophages can account for up to 50% of tumour mass and secrete many angio genic factors. Furthermore. tumour hypoxia is thought to play a major role in the activation of macrophages and the regulation of angiogenesis. In thi s paper, we demonstrate a strong correlation between hypoxia and the recrui tment of immune cells binding to IgG in 8 experimental tumours. We provide evidence that IgG binding immune cells in 3 tumour lines are predominately composed of macrophages. Reduced oxygenation may act as a stimulus for recr uitment of immune cells to the tumour mass, and the detection of either IgG -positive host cells or macrophages may offer an alternative method for mon itoring tumour hypoxia. (C) 2001 Cancer Research Campaign.