Fig. 1.

The osteo-immuno-oncology triad. Development of immune cells from hematopoietic stem cells (HSCs) in bone marrow indicates that bone and immune system are in constant interaction (Ponzetti and Rucci, 2019). Interaction of bone resident cells (osteoclasts, osteoblasts, osteocytes) with the immune cells is crucial to maintain bone homeostasis. Further, establishment of an immunosuppressive microenvironment and failed anti-tumor immune responses promote bone colonization of tumor cells from advanced cancers of breast, prostate, and lung.