CAPG and breast cancer: In addition, proteomic methods have been used to characterise murine models of breast cancer spread to bone, including intracardiac injection models of bone metastasis.9 Our proteomic analysis of bone-homing and parental triple negative breast cancer cells derived from intracardiac injection murine models has identified a panel of potential bone metastasis biomarker candidates including macrophage actin-capping protein (CapG), the PDZ-domain containing adaptor protein GIPC1,10 and the cell motility regulator DOCK4.1