Cancer Cell Dormancy in the Bone Microenvironment.

purpose of the reviewCancer cell dormancy in the bone microenvironment presents a major obstacle to curative therapy across multiple cancer types. The bone harbours specialised pro-dormancy niches that promote the induction and long-term maintenance of dormant cancer cells. Many cancers originate in or metastasise to bone, but share the phenomenon of dormancy, which enables therapy evasion and later reactivation to cause disease relapse. This review provides recent updates in preclinical and clinical findings regarding dormancy in bone. RECENT

findingsStudies have identified specific cell types including bone lining cells and Nestin + NG2 + MSCs as pro-dormancy niche cells. Newly identified signalling pathways, such as autophagy, have been found to support dormancy, with degrees of built-in redundancy. These advances have led to ongoing clinical trials in this space that mean new dormancy-targeting therapies, such as the autophagy inhibitor hydroxychloroquine, are on the horizon. This review explores extrinsic and intrinsic regulators of cancer cell dormancy in the bone microenvironment and highlights recent advances in development of therapies that can target cancer cell dormancy.