Figure 9: Schematic diagram summarizing the regulatory role of the Id1/IGF2/VEGF/VEGFR1 cascade in oesophageal cancer progression.

IGF2 secreted by Id1-expressing cancer cells activates fibroblasts to secrete VEGF which exerts paracrine effects in the tumour microenvironment, as well as instigates VEGFR1+ bone marrow cells in the tumour macroenvironment to facilitate distant metastasis.