CD8A and cancer: However, in the context of cancer, one study has indicated that CARMA1 is critical for controlling transplantable tumors (116); although, it remains unclear whether this effect is solely due to the deficiency of CARMA1 in CD8 T cell function or is also influenced by the lack of CARMA1-deficient CD4 T cell help to CD8 T cells, as suggested by a recent investigation (69).