From:  Targeting tumor transition windows

 Major mechanisms of tumor plasticity and their roles in therapy resistance.

Plasticity mechanismBiological processKey regulators and pathwaysRepresentative tumor typesTherapeutic implications
Cancer stem cell (CSC) plasticityDynamic interconversion between stem-like and differentiated tumor cell states, allowing tumor cells to regain tumor-initiating capacity and therapy resistanceDevelopmental signaling pathways (Wnt/β-catenin, Notch, Hedgehog), stress-response transcription factors, chromatin remodeling programs [33, 34]Breast cancer, glioblastoma, colorectal cancer, pancreatic cancerPromotes tumor regeneration after therapy and contributes to relapse; targeting stemness signaling pathways may suppress tumor re-initiation
Phenotypic switching (EMT/MET and related programs)Reversible transitions between epithelial, mesenchymal, and intermediate states enabling adaptation to environmental stress and therapeutic pressureEMT transcription factors (SNAIL, TWIST, ZEB), transforming growth factor beta (TGF-β) signaling, MAPK signaling, transcriptional stress programs [35, 36]Breast cancer, melanoma, lung cancerEnhances invasiveness, metastatic potential, and tolerance to targeted therapies and chemotherapy
Lineage plasticity and transdifferentiationTumor cells adopt alternative lineage identities distinct from their original differentiation program, often under therapeutic pressureTranscription factor reprogramming, epigenetic remodeling, loss of lineage-defining regulators [37, 38]EGFR-mutant lung adenocarcinoma transitioning to small-cell phenotype; prostate adenocarcinoma transitioning to neuroendocrine prostate cancer; melanoma dedifferentiationEnables tumors to bypass therapies targeting lineage-specific pathways and signaling dependencies
Epigenetic state switchingLarge-scale transcriptional reprogramming driven by chromatin remodeling and enhancer landscape changes without permanent genetic mutationChromatin remodeling complexes, histone modifiers, enhancer rewiring, transcription factor network reorganization [39, 40]Multiple tumor types including melanoma, glioblastoma, and breast cancerFacilitates rapid adaptive responses to therapy and contributes to reversible drug-tolerant states
Microenvironment-driven plasticityExtrinsic signals from the tumor microenvironment drive phenotypic transitions and adaptive tumor cell statesHypoxia signaling (HIF pathways), inflammatory cytokines, stromal growth factors, extracellular matrix signaling [41, 42]Solid tumors including pancreatic cancer, lung cancer, and colorectal cancerMicroenvironmental signals promote survival, stemness, and therapy resistance; targeting tumor-stroma interactions may disrupt adaptive plasticity

EGFR: epidermal growth factor receptor; EMT: epithelial-mesenchymal transition; MAPK: mitogen-activated protein kinase; MET: mesenchymal-epithelial transition.