The Role of Tumour-Associated Macrophages in Nephron Cancer

Author(s): Sofia Raffaele

TAMs (tumour associated macrophages) are a crucial component of the tumour stroma. They begin as blood monocytes drawn to the tumour by chemokine’s and cytokines generated by the tumour cells, and under the guidance of the tumour microenvironment, they mature into a powerful population of cells that support the growth of the tumour. TAMs have been shown to directly increase angiogenesis and tumour cell growth. TAMs also promote tumour propagation by creating extracellular matrix remodelling enzymes and effectively block immune response by producing immunosuppressive cytokines. Numerous investigations were conducted to clarify the involvement of TAM in tumour development in renal cell carcinoma (RCC). It has been shown that a higher density of TAMs is linked to worse patient survival using the pan-macrophages marker CD68 and the type 2 macrophage (M2) markers CD163 and CD206 [1].

Several markers that are quite characteristic for type 1 macrophages (M1) were also defined, despite the fact that the majority of researches in RCC are focused on the M2 population. TNF, IL-1, IL-6, and CCL2 were shown to be produced by macrophages that were isolated from RCC tumours. Conclusion: RCC is a perfect example of a tumour with a hybrid TAM phenotype that exhibits both M1 and M2 characteristics. TAMs also appear to be a promising therapeutic target. Additional research is required to identify RCC- specific TAM indicators with high predictive value and/or that may be used for therapeutic targeting [2].