Cytokine expression in the ileum and colon. Cytokine expression in the ileum and colon. Cytokine expression was assessed using Luminex xMAP technology. Data, mean ± SEM (pg/mL). A two-way ANOVA with Tukey post hoc was performed to identify statistical significance. IL1β expression increased in the ileum of WT animals treated with irinotecan compared with control (#, P = 0.0394, 24 hours; #, P = 0.0036, 48 hours). Only a significant decrease was seen in BALB/c-Tlr4−/−billy mice (#, a change from baseline in WT mice; ^, a change from baseline in BALB/c-Tlr4−/−billy mice, where P < 0.05). BALB/c-Tlr4−/−billy mice lacked an IL6 response at 6 hours, with significantly lower expression compared with WT mice (**, P = 0.0002 ileum; **, P = 0.0005 colon). TNFα expression peaked at 24 hours in the ileum of WT mice treated with irinotecan (#, P = 0.0113). This was significantly elevated relative to BALB/c-Tlr4−/−billy mice (*, P = 0.0166), which showed no elevation in TNFα (P > 0.05). No change was seen in the anti-inflammatory cytokine IL10. Hannah R. Wardill et al. Mol Cancer Ther 2016;15:1376-1386 ©2016 by American Association for Cancer Research