Overall, the correlation coefficient, including both Ki67 and PCNA, showed that most BMPs, BMP receptors and antagonists were negatively correlated with the proliferation status of breast cancer with the leading genes: GDF10, BMP4, TGFBR2, TGFBR3 and GDF3, whilst DAND5, BMP8B, BMPR1A, Smad2 and SOST were positively correlated with proliferation markers in the TCGA breast cancer cohort. This evidence concerns the gene SMAD2 and breast cancer.