To assess whether tumor-associated mast cells could respond to IL-33, we FACS purified the c-Kit+/FcεR1+ mast cells from the submucosal antrum of WT and gp130FF mice using stomachs from gp130FF; c-KitW-sh/W-sh mice as a specificity control for our purification strategy (Supplementary Fig. 5c). The gene discussed is KIT; the disease is neoplasm.