Given that tumors, including invasion fronts, in Apc/Dok3 mice did not show any increased infiltration of CD4+ and CD8+ T cells in comparison with Apc mice (Fig. 5A, B, and D), these lymphocytes might exert distal effects, for instance, via exosomes, because immune cell–derived exosomes are known to regulate cancer progression and metastasis (36). This evidence concerns the gene CD8A and cancer.