P2Y12 seems to mediate also bone loss under pathological conditions including cancer. In a mouse model of bone metastasis, clopidogrel increased bone mineral density and trabecular bone volume compared to controls (Su et al., 2012). Accordingly, in a mouse model of tumor-associated bone loss, the P2Y12 deficiency protected the animals from trabecular bone loss. Moreover, in the P2Y12-/- mice, the number and surface of osteoclasts significantly increased in the tumor-bearing wild-type animals, was similar to the controls (Su et al., 2012).