The results indicate that, compared with the PBS and LM∆ and LI∆ group mice, the protein expression levels of arginase-1 (ARG-1), indoleamine 2,3-dioxygenase (IDO), and inducible nitric oxide synthase (iNOS) in tumor tissues of the E6E7 group mice showed a decreasing trend (P > 0.05), while the protein expression levels of IL-10 and transforming growth factor-β1 (TGF-β1) did not show a notable change (Fig. 6K–P). Here, IDO2 is linked to neoplasm.