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Immunoediting

Immunoediting, commonly referred to as cancer immunoediting, is a multifaceted process in which the immune system both safeguards the host against nascent tumors and shapes the immunogenicity of surviving cancer cells through selective pressures.^[1] This dynamic interplay integrates immunosurveillance with tumor progression, comprising three sequential phases: elimination, where innate and adaptive immune responses detect and destroy transformed cells before they become clinically apparent; equilibrium, in which the immune system maintains a balance by controlling tumor proliferation without complete eradication, often persisting for extended periods; and escape, during which tumors acquire mechanisms to evade immune detection, leading to uncontrolled growth and metastasis.^[2] Originally conceptualized in the early 2000s and formalized in 2011, immunoediting highlights the immune system's dual role in suppressing oncogenesis while inadvertently promoting the evolution of less immunogenic tumor variants.^[3]^[1] Key mechanisms driving immunoediting include the recognition of tumor antigens by cytotoxic T cells and natural killer cells, mediated by interferons and major histocompatibility complex molecules, which initiate the elimination phase.^[4] In the equilibrium phase, chronic immune pressure fosters tumor heterogeneity, selecting for cells with downregulated antigen presentation or upregulated immunosuppressive factors like PD-L1.^[2] During escape, tumors exploit the microenvironment by recruiting regulatory T cells and myeloid-derived suppressor cells, further dampening effector responses.^[4] These processes underscore immunoediting's implications for oncology, as they explain tumor dormancy, resistance to therapies, and variable patient outcomes in immunotherapy.^[1] Recent advances emphasize targeting immunoediting phases to enhance treatments, such as immune checkpoint inhibitors that reinvigorate T-cell activity in the equilibrium or escape stages, and neoantigen vaccines that bolster elimination by priming adaptive immunity.^[2] Lifestyle factors, including exercise and nutrition, have also been shown to support early immunosurveillance, potentially delaying progression to later phases.^[2] Overall, understanding immunoediting provides a framework for personalized cancer strategies, integrating genomic profiling of tumor antigens with immunomodulatory interventions to disrupt immune evasion.^[5]

Overview

Definition

Immunoediting refers to the dynamic process by which the immune system shapes the immunogenicity of developing tumors or pathogens through a dual mechanism of immune surveillance and immune selection. In immune surveillance, the system detects and eliminates aberrant cells or infected cells expressing immunogenic antigens, thereby protecting the host from malignancy or infection. Concurrently, immune selection exerts selective pressure that favors the survival and outgrowth of variants with reduced immunogenicity, allowing them to evade immune detection and destruction.^[6]^[7] This process extends beyond mere immune surveillance, which is limited to the initial elimination of threats, by emphasizing the "editing" role where ongoing immune interactions sculpt the antigenic profile of surviving populations. In tumors, this results in the promotion of less visible or more suppressive clones; similarly, in pathogens such as viruses, it drives the evolution of strains that downregulate antigen presentation or inhibit key immune signaling pathways. The distinction highlights how immune pressure not only curbs but also inadvertently fosters immune-resistant entities, transforming potential threats into persistent ones.^[3]^[8] Central to understanding immunoediting is its framing within a three-phase model—elimination, equilibrium, and escape—which delineates the temporal progression from protective immunity to potential host compromise. From an evolutionary standpoint, immunoediting acts as a selective force akin to natural selection, wherein immune responses drive the adaptation of tumor or pathogen populations toward clones that are proficient in resisting immune-mediated elimination. This adaptive dynamic underscores the complex interplay between host defense and threat evolution in immunocompetent individuals.^[6]^[7]

Historical Development

The concept of immune surveillance against tumors traces its origins to early 20th-century immunology, with Paul Ehrlich proposing in 1909 that the immune system prevents the outgrowth of nascent transformed cells, a notion he termed "horror autotoxicus" to describe the avoidance of self-reactivity while protecting against malignancy.^[9] This idea laid foundational groundwork for understanding immune-tumor interactions, emphasizing the role of host defenses in suppressing carcinogenesis. Building on Ehrlich's insights, Frank Macfarlane Burnet's 1957 clonal selection theory provided a mechanistic framework for adaptive immunity, positing that lymphocytes clonally expand in response to antigens, including potential tumor neoantigens, thereby serving as a precursor to modern surveillance concepts.^[10] Burnet's theory shifted focus toward the specificity and memory of immune responses, influencing subsequent hypotheses on how the immune system might routinely eliminate aberrant cells. The term "immunoediting" was formally coined in a seminal 2002 review by Robert D. Schreiber and colleagues, who refined the cancer immunosurveillance hypothesis into a dynamic three-phase model—elimination, equilibrium, and escape—describing how the immune system both eradicates tumors and sculpts surviving variants to evade detection. This framework integrated historical surveillance ideas with emerging evidence of immune selection pressures on tumor evolution. Key experimental support came from 2001 studies using immunodeficient mouse models, such as RAG2-deficient mice, which demonstrated increased incidence of immunogenic sarcomas upon carcinogen exposure compared to wild-type counterparts, revealing that adaptive immunity not only prevents tumor formation but also edits for less recognizable clones. In the 2010s, the immunoediting paradigm expanded beyond cancer to pathogen-host interactions, particularly in chronic infections, where analogous phases describe immune selection of viral or bacterial variants, as highlighted in reviews linking tumor and infectious disease immunology.^[11] A 2014 review further integrated new data on the equilibrium phase, emphasizing persistent immune-tumor standoffs and the role of interferons in maintaining dormancy. Post-2020 refinements, driven by single-cell sequencing, have illuminated clonal evolution during editing; for instance, 2022 DNA barcoding studies in murine models tracked how immune pressure selects transcriptionally distinct tumor subclones.^[10] These advances underscore immunoediting's ongoing relevance in revealing adaptive immune dynamics.

The Three Phases

Elimination Phase

The elimination phase of immunoediting represents the initial stage in which the immune system detects and destroys nascent transformed or infected cells, preventing the development of detectable tumors or persistent infections. This process begins with the recognition of altered-self signals, such as damage-associated molecular patterns (DAMPs) released from stressed or dying cells, which activate innate immune components including natural killer (NK) cells and macrophages. These innate effectors bridge to adaptive immunity by promoting antigen presentation to CD8+ T cells, which recognize tumor-specific antigens via major histocompatibility complex class I (MHC-I) molecules. In competent hosts, this coordinated response eradicates immunogenic variants before they proliferate into clinically apparent disease. Key mechanisms driving elimination involve direct cytotoxicity and cytokine-mediated apoptosis. NK cells and CD8+ T cells form immunological synapses with target cells, releasing perforin to permeabilize the plasma membrane and granzymes to activate intracellular caspases, thereby inducing rapid cell death. Concurrently, interferon-gamma (IFN-γ) secreted by these lymphocytes upregulates MHC-I expression on target cells for enhanced recognition while also sensitizing them to apoptosis through pathways like Fas-FasL interactions and STAT1 signaling. Macrophages contribute by phagocytosing debris and secreting pro-inflammatory cytokines that amplify the response. These mechanisms collectively ensure the destruction of nascent lesions in most instances. Experimental evidence for the elimination phase derives from carcinogen-induced tumor models in mice, where wild-type immunocompetent hosts exhibit significantly reduced tumor incidence compared to immunodeficient counterparts. For instance, administration of the chemical carcinogen methylcholanthrene (MCA) to wild-type mice results in tumor development in approximately 20% of cases, whereas recombination-activating gene 1-deficient (RAG-1^{-/-}) mice, lacking adaptive immunity, develop tumors in about 60% under similar conditions.^[12] Severe combined immunodeficient (SCID) mice similarly show heightened susceptibility, underscoring the protective role of both innate and adaptive arms. A specific example is the elimination of ultraviolet (UV)-induced skin lesions, where UV irradiation upregulates NKG2D ligands like Rae-1 on keratinocytes, enabling NK cells and γδ T cells to recognize and lyse precancerous cells via the NKG2D receptor. This phase is typically subclinical and transient, resolving without overt pathology in the majority of potential oncogenic events and averting clinical disease. Failure to fully eliminate transformed cells, however, allows progression to the equilibrium phase, where a balance between immune control and residual tumor persistence may emerge.

Equilibrium Phase

The equilibrium phase of cancer immunoediting represents an intermediate stage where the immune system establishes a dynamic balance with surviving tumor cells, preventing their outgrowth while allowing the selection and persistence of less immunogenic variants. In this phase, ongoing immune recognition, primarily mediated by adaptive immune components such as cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells, limits tumor proliferation by continuously eliminating the most antigenic clones. However, subdominant tumor cell populations with reduced antigenicity or enhanced survival mechanisms evade complete eradication, surviving in a dormant or slowly dividing state and accumulating genetic mutations that further sculpt their immunogenicity. This selective pressure results in a sculpted tumor population that is qualitatively distinct from the original transformed cells, favoring variants with downregulated major histocompatibility complex (MHC) class I expression or altered antigen processing pathways. Key features of the equilibrium phase include chronic inflammation and a finely tuned cytokine milieu that maintains immune control without resolution. Cytokines such as interferon-gamma (IFN-γ) and interleukin-12 (IL-12) sustain antitumor activity by activating immune effectors, while counter-regulatory factors like transforming growth factor-beta (TGF-β) promote tolerance and limit excessive inflammation, creating a balanced environment. Additionally, prolonged immune engagement can lead to T-cell exhaustion, characterized by reduced effector function and upregulation of inhibitory receptors, which contributes to the stasis but also facilitates variant selection. This phase often involves localized immune privilege sites, such as hair follicles or bone marrow niches, where tumor cells persist with minimal detectable burden.^[13] Evidence for the equilibrium phase has been robustly demonstrated in preclinical models, particularly through adoptive transfer experiments in immunocompromised mice. For instance, in methylcholanthrene-induced sarcoma models, reconstitution of RAG1-deficient mice (lacking adaptive immunity) with wild-type splenocytes or purified T cells controls but does not eradicate occult tumors, maintaining them in a non-proliferative state for extended periods while selecting for immunologically edited variants. These experiments reveal that functional adaptive immunity is essential for sustaining equilibrium, as tumors rapidly progress to outgrowth in its absence. The equilibrium phase can persist for months to years in murine models and potentially decades in humans, often remaining asymptomatic with low tumor burden detectable only through advanced imaging or molecular assays. A hallmark marker of this editing process is the upregulation of programmed death-ligand 1 (PD-L1) on tumor cells, induced by IFN-γ signaling as an adaptive response to immune pressure, which dampens T-cell activity and reinforces the stasis. Prolonged equilibrium may eventually tip toward the escape phase if editing yields variants capable of evading immune detection.

Escape Phase

The escape phase of immunoediting represents the culmination of the immune-tumor interaction, where variants sculpted during the preceding equilibrium phase outgrow immune control, resulting in progressive disease. This transition occurs when the balance tips in favor of the tumor due to accumulated adaptations that render it immunologically inert or actively suppressive. In this phase, the immune system fails to constrain tumor expansion, leading to clinically detectable malignancy or persistent infection.^[14] Key triggers for escape include the loss of antigen presentation, such as downregulation or complete loss of major histocompatibility complex class I (MHC-I) molecules, which prevents recognition by cytotoxic T cells. This mechanism is prevalent in various cancers, where tumor cells evade T cell-mediated lysis through genetic mutations, epigenetic silencing, or transcriptional repression of MHC-I components. Additionally, the establishment of an immunosuppressive tumor microenvironment, characterized by the recruitment and expansion of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), further dampens effector immune responses by secreting inhibitory cytokines like TGF-β and IL-10. Immune checkpoint dominance, including overexpression of PD-L1 or CTLA-4 ligands, also promotes T cell exhaustion and anergy, facilitating unchecked tumor proliferation.^[15]^[16]^[17]^[18]^[16] The primary outcomes of the escape phase are overt clinical manifestations, such as rapid tumor growth in cancer or chronic persistence in infections, driven by the dominance of low-immunogenic variants. For instance, in melanoma models, MHC-I-negative clones emerge and expand under immune pressure, contributing to metastatic progression. Longitudinal studies in cancer patients have identified pre-clinical signatures of equilibrium, such as persistent low-level inflammation and antigen-specific T cell responses, that predict subsequent escape and tumor advancement. These edited tumors exhibit reduced immunogenicity, rendering them less responsive to standard therapies like chemotherapy or radiation, as the loss of neoantigens and altered surface markers impairs immune reactivation.^[14]^[15]^[19]^[20]^[14] A specific example of escape in lymphoma involves mutations in the beta-2-microglobulin (B2M) gene, which is essential for MHC-I assembly and surface expression. B2M loss-of-function mutations, observed in up to 20-30% of diffuse large B-cell lymphomas, abolish MHC-I presentation and enable immune evasion from both T cells and natural killer cells, promoting aggressive disease progression. This adaptation not only underscores the selective pressure of immunoediting but also highlights vulnerabilities exploitable by therapies targeting alternative immune pathways.^[21]^[22]

Molecular Mechanisms

Immune Cell Involvement

Innate immune cells are pivotal in the initial recognition and destruction of transformed cells during immunoediting, operating independently of antigen-specific mechanisms. Natural killer (NK) cells execute MHC class I-independent killing of tumor cells by recognizing stress-induced ligands, such as MICA/MICB, through activating receptors like NKG2D, leading to perforin- and granzyme-mediated cytotoxicity.^[23] This process is critical for eliminating nascent tumors in mouse models of sarcoma and carcinoma, where NK cell depletion results in accelerated tumor outgrowth. Macrophages complement NK cell activity by phagocytosing opsonized tumor targets, a function upregulated by interferon-gamma (IFN-γ) produced during early immune activation; blockade of the CD47-SIRPα "don't eat me" signal enhances this phagocytosis in lymphoma and breast cancer models.^[24] Adaptive immune cells drive antigen-specific responses that sculpt tumor immunogenicity across immunoediting phases. CD8+ T cells serve as primary effectors, recognizing tumor antigens presented by MHC class I via the T cell receptor (TCR), and inducing apoptosis through perforin, granzymes, and Fas ligand. In methylcholanthrene (MCA)-induced sarcoma models, CD8+ T cells eliminate immunogenic variants while sparing less antigenic ones, illustrating their selective pressure on tumor evolution.^[7] CD4+ T helper cells support this by licensing dendritic cells through CD40L interactions and secreting cytokines like IFN-γ and tumor necrosis factor (TNF), which amplify macrophage and NK cell functions; in Kras-driven hepatocellular carcinoma models, CD4+ T cells collaborate with macrophages to clear premalignant hepatocytes.^[25] Regulatory T cells (Tregs), characterized by Foxp3 expression, modulate immunoediting by suppressing excessive antitumor responses, thereby maintaining immune homeostasis. Tregs inhibit CD8+ T cell and NK cell activation via contact-dependent mechanisms (e.g., CTLA-4-mediated competition for CD80/CD86) and secretion of immunosuppressive cytokines such as IL-10 and TGF-β, which limits inflammation in the tumor microenvironment. In equilibrium maintenance, Tregs prevent complete tumor eradication while curbing destructive autoimmunity; depletion of Tregs in disseminated tumor models shifts the balance toward elimination. As immunoediting progresses from early phases to escape, adaptive immune cells undergo functional adaptations, including T cell exhaustion marked by upregulation of inhibitory receptors. On CD8+ T cells, PD-1 and TIM-3 accumulate in chronic tumor antigen exposure, impairing cytokine production (e.g., IFN-γ) and proliferative capacity; dual blockade of these pathways restores antitumor efficacy in mouse tumor models more effectively than single targeting.^[26] This exhaustion contributes to phase transitions by reducing effector function against persistent tumors. Quantitative dynamics, such as effector-to-target (E:T) ratios, influence immunoediting outcomes in experimental settings. In mouse cytotoxicity assays modeling tumor-immune interactions, E:T ratios above 10:1 promote rapid elimination of target cells by CD8+ T cells and NK cells, whereas ratios below 5:1 allow tumor persistence and editing, as observed in OT-I TCR transgenic models of lymphoma.^[27] These ratios highlight how immune cell abundance relative to tumor burden dictates phase dominance in vivo.

Tumor and Pathogen Adaptations

Tumors and pathogens under immune pressure evolve adaptations that diminish their visibility to the immune system, primarily through genetic mutations, epigenetic modifications, and alterations to the surrounding microenvironment. These changes allow less immunogenic variants to survive and proliferate, sculpting the population toward immune escape. In tumors, antigen loss variants arise from mutations in genes critical for antigen presentation, such as TAP1, TAP2, and B2M, which impair MHC class I expression and reduce recognition by CD8+ T cells. For instance, biallelic inactivation of B2M eliminates surface MHC-I, observed in approximately 29% of advanced melanomas (including mutations, deletions, or loss of heterozygosity) and associated with immunotherapy resistance.^[28] Similarly, TAP1/2 deficiencies, prevalent in 10-80% of colorectal and cervical cancers, disrupt peptide transport to MHC-I, further enabling evasion.^[29] Epigenetic silencing provides another layer of adaptation, where tumors methylate promoters of immunogenic antigens to suppress their expression without permanent genetic loss. The cancer-testis antigen NY-ESO-1, often hypomethylated and expressed in tumors to drive oncogenesis, can be re-silenced via DNA hypermethylation under T-cell pressure, reducing immunogenicity and promoting outgrowth of edited clones. This mechanism is reversible, as DNA methyltransferase inhibitors like 5-aza-2’-deoxycytidine reactivate NY-ESO-1, enhancing T-cell recognition in preclinical models of glioma and NSCLC.^[30] Complementing these intrinsic changes, tumors secrete immunosuppressive factors such as TGF-β and IDO to remodel the microenvironment, recruiting regulatory T cells and myeloid-derived suppressor cells while inhibiting effector T-cell function. TGF-β, produced by tumor cells and cancer-associated fibroblasts, polarizes neutrophils into an N2 pro-tumor phenotype and induces T-cell exhaustion, while IDO depletes tryptophan to anergize T cells and boost Treg activity, fostering tolerance in the tumor niche.^[31]^[32] Pathogens exhibit analogous adaptations, particularly through latency programs that downregulate immunogenic proteins to persist amid host immunity. In Epstein-Barr virus (EBV), latency type 0 or I minimizes expression of latent membrane protein 1 (LMP1), a potent antigen that mimics CD40 signaling and triggers T-cell responses; downregulation occurs via epigenetic silencing with H3K9me3 histone modifications and DNA methylation, allowing infected B cells to evade detection in healthy carriers. This selective pressure mirrors tumor immunoediting, where less antigenic viral states dominate post-acute infection. Evidence from whole-genome sequencing of tumor clones before and after immune editing reveals selective sweeps favoring variants with MHC-I defects or immunosuppressive traits; for example, longitudinal analyses in colorectal metastases show parallel evolution of immune-escaping subclones under T-cell selection. These findings underscore how immune pressure imprints genomic scars, enriching for adapted populations.^[33]^[34]

Clinical Relevance

In Cancer

Immunoediting plays a central role in oncogenesis by shaping tumor evolution through immune-mediated selection pressures, applying the three phases—elimination, equilibrium, and escape—specifically to the tumor microenvironment where nascent cancer cells must evade host immunity to progress.^[1] In solid tumors such as breast and lung cancers, this process promotes intratumor heterogeneity by favoring the survival and proliferation of less immunogenic clones that downregulate antigen presentation or upregulate immunosuppressive factors, leading to diverse subpopulations within the tumor mass.^[35] In contrast, hematologic malignancies exhibit less pronounced heterogeneity driven by immunoediting, as their liquid tumor nature and shared hematopoietic origin with immune cells result in more uniform clonal dynamics and reliance on intrinsic immune dysregulation rather than spatial evasion strategies.^[36] Diagnostic markers for assessing the stage of immunoediting in cancer include neoantigen burden and tumor-infiltrating lymphocyte (TIL) infiltration, which provide insights into the tumor's immune interaction history. High neoantigen burden, reflecting a dense array of tumor-specific mutations, often indicates an early elimination or equilibrium phase where immune pressure is actively sculpting the tumor, whereas low burden in advanced tumors signals escape through edited, less recognizable variants. Similarly, elevated TIL infiltration, particularly CD8+ T cells, serves as an indicator of the equilibrium phase, where ongoing immune containment correlates with denser lymphocytic presence in the tumor core and invasive margin.^[37] Epidemiological studies link altered immunoediting to higher cancer rates in immunocompromised patients, such as solid organ transplant recipients on immunosuppressive therapy, where reduced immune surveillance allows more tumors to progress without effective editing, resulting in increased incidence of skin, lymphoid, and other malignancies.^[38] In these populations, the diminished equilibrium phase leads to faster escape, with tumors displaying signatures of unchecked outgrowth rather than refined immune evasion.^[39] A notable case study of immunoediting in colorectal cancer involves microsatellite instability-high (MSI-high) phenotypes, where defective DNA mismatch repair generates a high mutational load, prompting robust initial immune recognition and TIL infiltration during the elimination phase. However, surviving clones undergo editing to reduce neoantigen expression or acquire resistance mutations, enabling equilibrium and eventual escape, as evidenced by genetic traces of immune selection in MSI-high tumors.^[40] This process highlights how MSI-high colorectal cancers, despite their immunogenicity, evolve heterogeneous subpopulations that evade sustained immune control.^[41]

In Infectious Diseases

Immunoediting in infectious diseases refers to the process by which the host immune system shapes the evolution of pathogens, particularly in chronic infections, through selective pressure that favors variants capable of evading immune detection or control. This dynamic is most evident in persistent viral infections, where high replication rates and error-prone polymerases generate diverse quasispecies populations that undergo immune-driven selection. Unlike acute infections, chronic pathogens like viruses and certain bacteria establish a prolonged interaction with the host, mirroring the equilibrium phase of immunoediting observed in other contexts, where immune responses contain but do not eradicate the pathogen.^[8] In human immunodeficiency virus (HIV) infection, immunoediting manifests through the emergence of escape mutants that evade CD8+ T cell recognition via mutations in epitopes presented by major histocompatibility complex class I (MHC-I) molecules. These mutations, often occurring at HLA-binding sites, allow HIV to reduce viral fitness costs while avoiding cytotoxic T lymphocyte (CTL) responses, leading to the dominance of immune-resistant variants over time. For instance, phylogenetic studies of HIV quasispecies in infected cohorts have demonstrated immune-driven bottlenecks, where transmission selects for a limited number of founder variants, and subsequent intra-host evolution favors escape mutations under CD8+ T cell pressure. Similarly, in hepatitis C virus (HCV) infection, T cell escape mutations in epitopes, including those derived from the core protein, predict the outcome of infection by enabling viral persistence. Seminal work has shown that positive selection pressure from CTLs drives mutations in MHC class I-restricted epitopes, with variants exhibiting altered peptide processing or binding that diminish T cell recognition and contribute to chronicity.^[42]^[43] Bacterial pathogens also exhibit parallels to immunoediting, as seen in Mycobacterium tuberculosis (M. tuberculosis), where latency represents an equilibrium-like state in which the host immune response, particularly involving CD4+ and CD8+ T cells and interferon-gamma, controls bacterial replication without complete clearance. During this phase, the pathogen persists in granulomas, evading adaptive immunity through mechanisms such as antigen variation and inhibition of phagosome maturation, maintaining a dormant state that can reactivate upon immune compromise. In host-pathogen co-evolution during persistent infections, immune selection often favors low-virulence strains that balance replication with host survival, promoting long-term transmission; for example, in HIV and other chronic viruses, coevolutionary arms races lead to attenuated variants that persist without overwhelming the host.^[44]^[45]^[46] A key difference in immunoediting between infectious diseases and cancer lies in the kinetics, driven by the exceptionally high mutation rates of RNA viruses (10^{-3} to 10^{-5} errors per nucleotide per replication cycle), which enable rapid generation of escape variants within weeks to months, contrasting the slower somatic mutation accumulation in tumors over years. This accelerated pace in RNA viruses like HIV and HCV facilitates quicker transitions from immune recognition to evasion, heightening the challenge of achieving sterilizing immunity.^[47]^[8]

Therapeutic Implications

Immunotherapy Approaches

Immunotherapy approaches targeting immunoediting aim to intervene in the three phases—elimination, equilibrium, and escape—by enhancing immune recognition and effector functions against tumors that have adapted to evade detection.^[32] Phase-targeted therapies, such as immune checkpoint inhibitors, primarily disrupt the equilibrium phase and prevent progression to escape by blocking inhibitory signals that suppress T-cell activity. Anti-PD-1 inhibitors like nivolumab and pembrolizumab restore T-cell function, enabling reactivation of anti-tumor immunity in tumors under immune control.^[32] These agents have shown response rates of 30-40% in advanced melanoma, with durable remissions in responsive patients.^[32] Similarly, CTLA-4 blockade with ipilimumab reverses escape in melanoma by depleting regulatory T cells and promoting T-cell priming, achieving objective response rates of approximately 11% as monotherapy but demonstrating long-term survival benefits in metastatic cases.^[32]^[48] Combination approaches integrate multiple modalities to bolster the elimination phase and shift tumors from equilibrium back to immune clearance. Cancer vaccines, such as mRNA neoantigen vaccines, paired with adoptive T-cell therapy amplify early-stage immune responses by priming tumor-specific CD8+ T cells against nascent edited variants.^[32] For instance, combining neoantigen vaccines with tumor-infiltrating lymphocytes (TILs) has yielded response rates of about 50% in metastatic melanoma, enhancing infiltration and persistence of effector cells.^[32] Emerging tools like neoantigen-targeted autologous T-cell therapies address immunoediting by directing engineered cells against patient-specific mutated antigens that arise during tumor adaptation. In a 2025 phase 1 trial for checkpoint-refractory metastatic melanoma, BNT221—a personalized neoantigen-specific T-cell product—achieved stable disease in 67% of patients and tumor regression in 44%, indicating potential to counter antigen-loss variants in the escape phase.^[49] Overall success metrics in immunoediting-stage-stratified patients highlight higher efficacy in equilibrium-phase tumors using checkpoint inhibitors or combinations, compared to lower rates in fully escaped lesions.^[32] These outcomes underscore the value of tailoring interventions to the dominant immunoediting phase for improved clinical responses.^[32]

Challenges and Future Research

One major challenge in understanding immunoediting lies in the significant heterogeneity observed across different tumor types, where the tumor microenvironment (TME) varies dynamically due to interactions between immune and tumor cells, complicating generalized models of immune selection.^[4] This heterogeneity often results in intratumoral diversity, selecting for pre-existing genetic or epigenetic variants that resist immune pressure, thereby hindering uniform therapeutic responses.^[50] Additionally, distinguishing the phases of immunoediting—particularly the subclinical elimination and equilibrium stages from the overt escape phase—remains experimentally difficult in vivo, as these early processes precede detectable tumor outgrowth and lack clear biomarkers for real-time monitoring.^[51] Methodological limitations further impede progress, with much of the current knowledge derived from animal models that inadequately recapitulate human immune responses, such as incomplete reconstitution of human immune cells in humanized mice, leading to discrepancies in immunoediting dynamics.^[52] There is a pressing need for advanced real-time imaging techniques, like high-plex spatial transcriptomics and 3D microscopy, to capture phase transitions in situ, as existing approaches struggle to track the spatial evolution of immune-tumor interactions during editing.^[53] Unresolved questions persist regarding external modulators of immunoediting, including the role of the gut microbiome, which influences anti-tumor immunity through metabolites that can either enhance or suppress immune editing, yet its precise mechanisms in shaping tumor immunogenicity remain unclear.^[54] Similarly, the impact of aging on phase dynamics is underexplored, with evidence suggesting that immunosenescence leads to reduced natural killer cell activity and less effective editing in older individuals, potentially allowing more immunogenic tumors to escape detection.^[55] Future research directions emphasize AI-driven predictions of patient responses to immunotherapy using multi-omics data, enabling personalized immunotherapy strategies.^[56] Recent 2025 conferences, such as the SITC Spring Scientific, have highlighted advances in cellular therapies for solid tumors to address immunoediting, including strategies targeting both immune evasion and tumor angiogenesis.^[57]^[58] Complementing this, integrating multi-omics approaches—such as genomics, transcriptomics, and proteomics—holds promise for identifying phase-specific biomarkers, as demonstrated in studies refining prognostic models for immune checkpoint responses through comprehensive TME profiling.^[59] These advancements aim to overcome current therapeutic limitations by anticipating editing outcomes. Ethical considerations in designing immunoediting-targeted therapies center on balancing immune activation to counter tumor escape while mitigating risks of hyperactivation, such as autoimmunity and immune-related adverse events, which can arise from reversing immunosuppression in vulnerable patients.^[60] This requires rigorous informed consent processes and equitable access to emerging tools, ensuring that benefits outweigh potential harms in diverse populations.^[61]

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Although accumulation of the different immune cell subsets , such as solid tumors ... cancer immunoediting”. Depending on the context, the dual interaction ...
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Tumor Neoantigen Burden as a Biomarker for Immunotherapy and ...
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Tracing the Equilibrium Phase of Cancer Immunoediting in ...
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Jun 4, 2018 · A UCLA-led study has found how colon cancer alters its genes during development in order to avoid detection by the immune system.
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The selective outgrowth of HIV-1 genetic variants, which have mutations within or near CD8 T-cell epitopes, allows viral escape from CD8 T-cell immunity [1].
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https://www.nejm.org/doi/full/10.1056/NEJMoa1003466
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Tracing the Equilibrium Phase of Cancer Immunoediting in ...
The equilibrium phase of immunoediting is interesting since it represents a rate-limiting intermediate in cancer development that might be targetable for cancer ...
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Editorial: Challenges associated with identifying preclinical animal ...
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The Spatial Landscape of Progression and Immunoediting in ...
Here we integrate high-plex imaging, 3D high-resolution microscopy, and spatially resolved microregion transcriptomics to study immune evasion and immunoediting ...<|separator|>
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Jul 1, 2019 · Here, we review how immunometabolism may contribute to cancer escape from the immune system, as well as highlight an emerging role of gut microbiota.
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Considerations and Approaches for Cancer Immunotherapy in the ...
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AI & Machine Learning in Cancer Immunotherapy Design
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Integrated Multi-Omics Analysis Model to Identify Biomarkers ...
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Considerations for immunotherapy in patients with cancer and ...
By reversing immunosuppression with immunotherapy agents, immune attack against tumor can be restored, but often results in autoimmunity against normal cells.
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Ethical considerations of cellular immunotherapy for cancer - NIH
The main risk to patients in clinical trials is the risk of pain and complications caused by treatment. The benefits refer mainly to avoiding injury and ...