Antitumor effect of <i>Batf2</i> through IL-12 p40 up-regulation in tumor-associated macrophages

Significance The therapeutic activity of checkpoint blockers and toll-like receptor (TLR) agonists, which show some efficacy against malignancies, appears to at least partially result from the secretion of type-I IFNs. Thus, we hypothesized that type-I IFN-inducible transcription factors, such as basic leucine zipper transcription factor ATF-like 2 ( Batf2 ), might play a role in tumor immunity. Here, we investigated the role of Batf2 , especially its positive transcriptional activities, and evaluated its antitumor effect. This study shows that Batf2 has an antitumor effect through the up-regulation of IL-12 p40 in tumor-associated macrophages, which eventually induces the activation of CD8 + T cells and their accumulation within the tumor. Batf2 may be an important target in anticancer treatment with immune checkpoint blockers and TLR agonists.