To better understand the mechanisms leading to protection in Nod2ΔLyz2, the expression of Ccl2, Cxcl1 and genes related to cell functions, such as Tgfb, Il10, iNos, Areg, Cxcl13, and Ptgs2, was quantified by RT-qPCR on tumoral tissue at the end of the AOM/DSS protocol (Figure 3E, Supplementary Figure 3 and data not shown). This evidence concerns the gene CCL2 and infectious otitis media.