The inhibition by aspirin and indomethacin of osteolytic tumor deposits and hypercalcaemia in rats with Walker tumour, and its possible application to human breast cancer.

Walker carcinosarcoma cells cause in vitro osteolysis which may be inhibited by aspirin. In the rat, this tumour produces osteolytic bone deposits and hypercalcaemia, both of which can be prevented by aspirin and indomethacin, whereas soft tissue tumour deposits are unaffected by these drugs. Some human breast tumours cause in vitro osteolysis which may be inhibited by aspirin.