The pathogenesis of bone metastasis in solid tumors: a review

Owing to its frequent occurrence and severe clinical picture, bone metastasis is an important problem in the clinical course of tumor diseases. Bone metastasis develops when the physiological remodeling process is disrupted by tumor cells via the same molecular mechanisms used by native bone cells. The process includes molecular cross-talk between osteocytes and osteoblasts and osteoclasts. Osteolytic bone metastasis, most often seen in breast cancer, is characterized by promoted differentiation and function of osteoclasts and reduced osteoblast function.Tumor cells take advantage of factors released by bone tissue resorption, thus establishing a vicious cycle that promotes the metastatic process. In osteoblastic metastasis, most often seen in prostate cancer, osteoblast function and differentiation are promoted, while osteoclast activity is reduced, resulting in net gain of bone tissue. Mechanisms involved in the early stages of bone metastasis and cancer cell dormancy have been understudied studied, and their exploration may pave the way fot potential therapeutic strategies. Tumor affects the bone marrow microenvironment via exosomes, soluble facto's, and membrane-bound ligands. In this way, an initial lesion is established, which after a variable duration of disseminated tumor cells dormancy progresses to an overt condition. I he current review deals with basic mechanisms involved in bone metastasis formation and propagation. We illustrated a disparity between the diversity and number of factors included in the disease pathophysiology and the number of available and developing therapeutic options. We also examined new therapeutic strategies affecting molecular pathways.

Automated summary

Bone metastasis is a significant issue in the clinical course of tumor diseases, involving disruption of the physiological remodeling process by tumor cells via the same molecular mechanisms. The mechanisms involved in the early stages of bone metastasis and cancer cell dormancy are understudied, but their exploration may lead to potential therapeutic strategies.