TLR2 and neoplasm: KrasLSL–G12D/+ mice on a Tlr2−/− background (KrasLSL-G12D/+;Tlr2−/−) developed more tumors and had a significantly increased tumor burden compared with controls (KrasLSL-G12D/+;Tlr2+/+) (Figures 2A and 2B).