IL6 and colorectal cancer: To determine whether IL-6 plays an essential role in tumorigenesis of colorectal cancer, we used IL-6tm1Kopf mice, which are IL-6 gene-knockout mice, to generate colorectal neoplasms that result from the inflammatory insult induced by azoxymethane (AOM) and dextran sulfate sodium (DSS) (Figure 5D and 5E).