TGFB1 and neoplasm: Numerous studies, including our own, have defined and characterised the biology underpinning stromal-rich tumours compared with epithelium-rich (stromal-low) tumours, which is dominated by elevated transforming growth factor-β (TGF-β) signalling or other markers of mesenchymal/CMS4 biology.11–14 Elevation of TGF-β and stromal signalling cascades have been proposed as targets themselves, however no evidence has been shown that such biology is driving the differential outcomes in the ~50%–60% of stroma-rich tumours that eventually relapse, compared with those that do not.