Dynamic mutator states in cancer

Somatic mutation generation is fundamental to cancer initiation, progression, heterogeneity, and treatment resistance, yet mutagenic capacity is often interpreted primarily through constitutive defects in DNA replication and genome-maintenance pathways. Emerging evidence indicates that the probability, rate, and spectrum of newly acquired mutations can also vary with cellular physiology and environmental context. This Review examines metabolic and mitochondrial alterations, oncogenic replication stress, transcriptional and chromatin-associated processes, inflammatory and enzymatic mutagenesis, tumor-microenvironmental pressures, and therapy-associated adaptation as potential determinants of mutation generation. We distinguish mutation generation from DNA damage, genomic instability, accumulated mutation burden, mutational topography, and clonal selection, and evaluate these mechanisms according to the strength of evidence linking cellular or environmental perturbations to subsequent mutation acquisition. Building on classical mutator phenotypes and prior concepts of stress-induced, adaptive, and therapy-associated mutagenesis, we propose the framework of dynamic mutator states: coordinated cellular configurations in which mutagenic capacity differs from an appropriate reference state through mechanistically identifiable processes and is accompanied by altered acquisition, rate, or spectrum of new mutations. Such states may be transient, recurrent, persistent, or progressively stabilized during tumor initiation, spatial diversification, metastatic evolution, treatment adaptation, residual disease, and relapse. We further define experimental criteria for identifying dynamic mutator states, emphasizing prospective mutation measurement, temporal ordering, lineage resolution, perturbation, and reversal or rescue. Finally, we consider whether mutation-generating processes themselves could become therapeutic targets, thereby limiting the supply of new genetic variation available for subsequent selection. A state-based view of mutagenesis provides a framework for connecting cellular physiology to mutation acquisition and for determining when mutation supply becomes a dynamic and potentially actionable component of cancer evolution.