Thus, in CD8 T cells, c-Jun/AP-1 seems to act as a guardian of anti-tumor activity: by forming ternary complexes with NFAT it prevents monomeric NFAT from initiating the transcriptional program of exhaustion; by displacing JunB and BATF3 from regulatory regions it blocks the expression of exhaustion-associated genes. This evidence concerns the gene FOS and neoplasm.