IGFBP5 and breast carcinoma: A practical example of this collaborative relationship between IGFBP5 and the ECM in cancer is shown in a study demonstrating IGFBP5 can bind directly to vitronectin to facilitate adhesion of breast cancer cells to the mesenchymal ECM via interaction with α2β1 integrins, as opposed to the αVβ3 integrins that canonically act as the vitronectin receptor (37).