Translational models of prostate cancer bone metastasis.

Metastatic disease is the principal cause of prostate-cancer-related mortality. Our ability to accurately recapitulate the spread of prostate cancer to bone - the most common site of metastasis - is critical to the development of novel metastasis-directed therapies. Several translational models of prostate cancer bone metastasis have been developed, including animal models, cell line injection models, 3D in vitro models, bone implant models, and patient-derived xenograft models. The use of these models has led to numerous advances in elucidating the molecular mechanisms of metastasis and innovations in targeted therapy. Despite this progress, current models are limited by a failure to holistically reproduce each individual element of the metastatic cascade in prostate cancer bone metastasis. In addition, factors such as accurate recapitulation of immunobiological events and improvements in tumour heterogeneity require further consideration. Knowledge gained from historical and currently used models will improve the development of next-generation models. An introspective appraisal of current preclinical models demonstrating bone metastases is warranted to narrow research focus, improve future translational modelling, and expedite the delivery of urgently needed metastasis-directed treatments.