A major role of Batf3 in cDC1 is to sustain their expression of Irf8. Consistent with this, the development of cDC1 and their ability to cross-present cell-associated Ag are rescued in Batf3−/− animals transgenic for Irf8. Nevertheless, these mice still fail to control the growth of a regressor fibrosarcoma, likewise to Batf3−/− animals. This evidence concerns the gene MPPE1 and fibrosarcoma.