Mundy's 2002 review maps the molecular mechanisms by which breast, lung, and prostate cancers colonize and destroy bone. It identifies PTHrP and endothelin-1 as the key mediators of osteolytic and osteoblastic metastasis, respectively. The review establishes the vicious cycle framework and its direct therapeutic implications for bisphosphonate and targeted antibody use.
PTHrP does two things in hypercalcemia of malignancy: it drives bone resorption and increases renal tubular calcium reabsorption. Bisphosphonates block only the first mechanism.
When bisphosphonates fail to control hypercalcemia durably in a patient with advanced breast cancer, the renal component is why. PTHrP-neutralizing antibodies address both arms and are more complete therapy in preclinical models.
When you see osteolytic bone metastases, recognize that osteoclast inhibition does more than prevent fracture. By breaking the vicious cycle (blocking TGF-β and IGF1 release from resorbed bone), it may reduce tumor burden in bone — the mechanistic rationale behind bisphosphonate and denosumab use beyond skeletal-related event prevention.
Elevated serum alkaline phosphatase in a patient with known osteolytic metastases reflects a secondary local bone-forming repair response. It does not mean the lesion has converted to osteoblastic disease. Up to 25% of breast cancer bone metastases have blastic features and nearly all prostate cancer osteoblastic lesions have a resorptive component. Pure phenotypes are the exception, not the rule.
Mundy's 2002 review maps the molecular mechanisms by which breast, lung, and prostate cancers colonize and destroy bone. It identifies PTHrP and endothelin-1 as the key mediators of osteolytic and osteoblastic metastasis, respectively. The review establishes the vicious cycle framework and its direct therapeutic implications for bisphosphonate and targeted antibody use.
PTHrP does two things in hypercalcemia of malignancy: it drives bone resorption and increases renal tubular calcium reabsorption. Bisphosphonates block only the first mechanism.
When bisphosphonates fail to control hypercalcemia durably in a patient with advanced breast cancer, the renal component is why. PTHrP-neutralizing antibodies address both arms and are more complete therapy in preclinical models.
When you see osteolytic bone metastases, recognize that osteoclast inhibition does more than prevent fracture. By breaking the vicious cycle (blocking TGF-β and IGF1 release from resorbed bone), it may reduce tumor burden in bone — the mechanistic rationale behind bisphosphonate and denosumab use beyond skeletal-related event prevention.
Elevated serum alkaline phosphatase in a patient with known osteolytic metastases reflects a secondary local bone-forming repair response. It does not mean the lesion has converted to osteoblastic disease. Up to 25% of breast cancer bone metastases have blastic features and nearly all prostate cancer osteoblastic lesions have a resorptive component. Pure phenotypes are the exception, not the rule.