FN1 and breast carcinoma: For instance, exposing adipose stromal cells to breast cancer-cell secreted factors leads to the deposition of a high amount of stiff and unfolded FN.222 The conformational changes of tumor-associated FN increase the spatial separation between the integrin-binding sequence of FN (FNIII9–FNIII10), forcing cells to switch from α5β1 to αvβ3 binding, which is insensitive to the increased distance between FNIII9 and FNIII10.