To determine whether the action of DDR2 in breast tumor CAFs controlled β1 Integrin activity in vivo we freshly isolated primary MMTV-PyMT breast tumor organoids (200–500 cells) from WT, ubiquitous Ddr2-/-, and FSP1cre; Ddr2-/- breast tumor bearing mice and immediately cultured these in 3D collagen I matrices under hypoxic conditions (Hwang et al., 2019). Here, DDR2 is linked to breast neoplasm.