SMAD1 and breast carcinoma: Our data also suggest that FOXF2 mRNA level in combination with the mRNA levels of the FOXF2 target genes BMP4/SMAD1 or BRGs may be biomarkers for the prediction of breast cancer bone metastasis risk, and targeting the FOXF2-BMP/SMAD axis might be a promising therapeutic strategy to manage breast cancer bone metastasis.