BMP2 and disease of the tendon: Previous studies also showed that treatment with BMP-2 promotes osteo-chondrogenic differentiation of TSPCs in vitro, and when TSPCs were disposed with BMP-2 and then transplanted subcutaneously into immunocompromised mice, structures similar to osteotendinous junctions were formed (Bi et al., 2007), which were similar to the ectopic ossified structures observed in both the tendinopathy animal model (Lui et al., 2009) and human samples (Rui et al., 2012b).