It has been demonstrated that treatment with ATN-161, a fibronectin-derived peptide known to interfere with integrin α5β1 and αvβ3 binding, resulted in a marked decrease in the incidence and number of skeletal and soft tissue metastases after intracardiac injection of MDA-MB-231 BC cells in nude mice, suggesting also a possible role for these integrin heterodimers in BC osteotropism [17]. This evidence concerns the gene FN1 and breast cancer.