Figure 1.

In vivo, tumor infiltrating lymphocytes (TIL) found inside melanoma express high level of MAF. In vitro, overexpression of MAF can be induced by TCR triggering together with IL-6, TGFβ or both. Inside the tumor microenvironment, maf expression could also be promoted by the production of other factors such as hypoxia, amino acid deprivation, other cytokines produced by tumor cells or immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) or regulatory T cells (Treg). In CD8⁺ TILs, MAF enhances the expression of pdcd1, lag3, bcl6, il10 and further genes associated with exhaustion, leading to the impairment of T-cell function.