TREM-1 plays a pivotal role in inflammation-driven intestinal carcinogenesis. In the wild-type Trem1+/+ mouse model treated with azoxymethane (AOM) and dextran-sodium sulfate (DSS), TREM-1 was present in tumors but absent from the surrounding tumor-free mucosa. This suggests that TREM-1 mediates the recruitment of neutrophils into colon cancers and colitis-associated malignancies in the AOM/DSS model. The lack of TREM-1 signaling in Trem1−/− mice significantly reduces the development of intestinal tumors. Here, TREM1 is linked to infectious otitis media.