The sleeping threat: targeting cancer dormancy to transform metastasis therapy.

Metastatic cancer cell dormancy, wherein disseminated cancer cells (DCCs) persist in a quiescent state before reactivating to fuel metastasis, has emerged as a critical determinant of cancer relapse. In this Review, we synthesize recent advances in understanding the microenvironmental drivers of dormancy, including the role of niche-derived signals and extracellular matrix composition in maintaining DCC quiescence, as well as the epigenetic and transcriptional programmes, and chromatin remodelling that enforce and sustain dormancy. We also cover the mechanisms by which dormant DCCs evade immune surveillance, highlighting both innate and adaptive immune interactions, and the strategies tumours use to escape immune-mediated clearance. Although most data come from solid cancers, we also examine the biology of residual cells in haematologic malignancies that share key dormancy and relapse mechanisms with solid tumours. We also discuss how, despite these mechanistic insights, clinical translation remains limited, as available biomarkers or therapies targeting dormancy have yet to be effectively implemented. We conclude that by outlining the challenges and opportunities for leveraging dormancy biology, we may be able to prevent metastatic recurrence and improve patient outcomes.