One hypothesis is that leukemia and colorectal cancer models share common inflammatory mediators (like IL-6) that selectively suppress some microbes and encourage others (e.g., high IL-6 may be toxic to strict anaerobes or alter bile acids to the detriment of Firmicutes), whereas the LLC model might involve additional factors (like tumor-derived catecholamines or other immune factors) that have a different impact on the microbiome. This evidence concerns the gene IL6 and leukemia.