Introduction
FGFR signaling is central for cancer cell proliferation, migration, angiogenesis and survival; FGFR alterations have become clinically actionable in increasing number of cancer types. This study evaluated the incidence and characterization of numerous FGF/FGFR alterations in over 12,000 invasive breast cancers and highlighted the tremendous heterogeneity of FGF/FGFR alterations in various histologic and molecular subtypes as well as different metastatic sites of breast cancer. Further, the associations of FGFR alterations and resistance to therapies were shown in a large clinical database with matched molecular results.