IL1B and oral mucositis: Figure 4 illustrates immunostaining for iNOS, IL-1β, TNF-α and TGF-β RII in cheek pouches of hamsters subjected to 5-FU-induced oral mucositis (Figures 3c, 3g, 3k and 3o, respectively) on the 14th day of treatment compared with the weak staining observed in the Healthy control group (Figures.