Recent data have shown that overexpression of BMPs (especially BMP4 and BMP7) correlates with advanced human breast cancer.12, 13 It has also been demonstrated that inhibition of BMPR2 suppresses growth and viability of breast cancer cells.14 Furthermore, in our previous study, more prevalent expression of BMPR2 was found in dedifferentiated chondrosarcomas than conventional chondrosarcomas.15 However, the mechanisms of BMPR2 in regulating tumor growth and progression remain unclear. This evidence concerns the gene CLN5 and breast cancer.