These data were confirmed by immunofluorescent staining for CD31 (Supplementary Fig. 5b,c), as well as in the E0771 tumours where obesity increased CD31+ staining in E0771 tumours from DIO mice in an IL-1/IL-1R1-dependent manner (Fig. 4d). Here, IL1B is linked to obesity due to melanocortin 4 receptor deficiency.