Furthermore, we further found the increased protein level of CD11c (a DC marker) in tumor tissue after L. intestinalis treatment via immunohistochemistry (Figure 2j–k) and observed the upregulated mRNA expression level of DC-related genes Itgax, Flt3, and Batf in the L. intestinalis group in the tumor tissues of the AOM/DSS model (Figure S4a). Here, FLT3 is linked to infectious otitis media.