Yoneda et al (1997) have reported that osteolytic bone metastasis of breast cancer could be inhibited by combined treatment with bisphosphonate, a specific inhibitor of osteoclastic bone resorption, and tissue inhibitor of MMP (TIMP)-2, a natural inhibitor of MMPs. Since previous studies have shown that recombinant TIMP-1 and TIMP-2 inhibited bone resorption in vitro (Hill et al, 1993), TIMP-2 may suppress bone metastasis by inhibiting both tumour invasion and bone resorption. This evidence concerns the gene TIMP1 and breast carcinoma.