Malignant tumors continue to pose one of the most formidable challenges in modern medicine, persistently eluding the full efficacy of current therapeutic modalities. Despite significant advances in conventional treatments and the advent of first-generation immune checkpoint inhibitors (ICIs), the clinical landscape remains constrained by issues such as therapeutic resistance and modest response rates. In this evolving context, T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) has surfaced as a compelling candidate in the quest to enhance cancer immunotherapy outcomes, heralding a new era in immune checkpoint targeting.
TIGIT distinguishes itself by its broad expression across a spectrum of immune cells integral to anti-tumor immunity, notably T cells, natural killer (NK) cells, and regulatory T cells (Tregs). Mechanistically, TIGIT exerts a multifaceted immunosuppressive influence primarily through its competitive engagement with ligands CD155 and CD112. This competitive binding interrupts the activating signals mediated by CD226, a co-stimulatory receptor imperative for robust T and NK cell cytotoxic activity. The result is a suppressive tumor microenvironment that favors tumor immune evasion and sustains hypoxia-linked immunosuppression, complicating therapeutic intervention.
Intriguingly, TIGIT’s role transcends mere ligand competition. It has been observed to interfere with the cis-dimerization of CD226, further dampening cytotoxic signaling pathways. Moreover, TIGIT directly binds CD155 expressed on dendritic cells (DCs), hindering their maturation and function—an effect compounded by TIGIT-mediated induction of the anti-inflammatory cytokine interleukin-10 (IL-10). This cytokine milieu skews the immune response away from effective tumor eradication, simultaneously fostering Treg maturation and the elevated expression of the transcription factor Foxp3, a master regulator of immunosuppressive Tregs.
The clinical relevance of TIGIT expression has been substantiated across various malignancies, including breast, colorectal, and pancreatic cancers, where elevated TIGIT levels correlate with adverse patient outcomes. Comprehensive analyses of The Cancer Genome Atlas (TCGA) data reveal that heightened TIGIT expression in breast cancer tissues significantly associates with diminished overall survival rates and reduced progression-free intervals. These findings underscore TIGIT’s potential as a prognostic biomarker, with a sensitivity that, in some cases, surpasses that of programmed death-1 (PD-1), another well-characterized immune checkpoint.
Therapeutically, targeting TIGIT presents both challenges and opportunities. Monotherapy with TIGIT inhibitors has exhibited limited efficacy in clinical settings, prompting exploration of combinatorial strategies. Notably, dual blockade of TIGIT and PD-1 pathways has demonstrated profound immunologic synergy. The phase II CITYSCAPE trial exemplifies this approach, where the anti-TIGIT antibody tiragolumab, in conjugation with the anti-PD-1 agent atezolizumab, markedly improved objective response rates and progression-free survival in non-small cell lung cancer (NSCLC) patients compared to PD-1 inhibition alone. This synergy is attributed to TIGIT blockade’s capacity to reverse T-cell exhaustion and mitigate NK cell depletion, effectively overcoming mechanisms of PD-1 resistance.
Several TIGIT inhibitors are currently advancing through late-phase clinical trials, with agents such as vibostolimab, tiragolumab, and ociperlimab demonstrating promising profiles in solid tumors. Concurrently, innovative platforms are developing dual-target antibodies, exemplified by candonilimab, which concurrently targets TIGIT and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), aiming to amplify immunostimulatory effects while curtailing toxicity. These agents represent a new frontier in precision immunotherapy, designed to strategically dismantle tumor-induced immune suppression.
Future research directives are poised to refine this therapeutic landscape by identifying robust biomarkers predictive of response to TIGIT-targeted treatment, optimizing dosing regimens, and exploring combinatorial frameworks with metabolic or epigenetic modulators. The integration of these approaches promises to enhance the durability and breadth of clinical responses, potentially transforming the current paradigms of cancer management.
Fundamentally, TIGIT-centered immunotherapy embodies a translational strategy with the scope to transcend the heterogeneity and complexity of tumor immunobiology. By intricately modulating multiple axes of immune regulation, TIGIT inhibition offers a strategic lever to recalibrate antitumor immunity, thereby surmounting the resistance that plagues existing immunotherapeutic regimens. This positions TIGIT not merely as a novel checkpoint inhibitor but as a pivotal fulcrum for the next generation of cancer immunotherapy.
The evolving body of evidence positions TIGIT as a biomarker of paramount importance, one that may soon redefine patient stratification and therapeutic decision-making in oncology. Its superior specificity in delineating exhausted CD8+ T-cell phenotypes compared to PD-1 enhances its utility beyond a therapeutic target, extending into realms of prognostication and personalized medicine. This nuanced understanding underscores the imperative for comprehensive translational research to expedite TIGIT’s clinical application.
In summary, the burgeoning research landscape illuminates TIGIT as a vital node in the tumor-immune interface with multifarious implications for cancer progression and immune escape. Through direct and indirect mechanisms—ranging from ligand competition and inhibitory signaling to modulation of dendritic cell functionality and regulatory T cell activity—TIGIT orchestrates a profound immunosuppressive milieu that tumors exploit for survival and growth. Its targeted inhibition holds transformative potential, promising to reshape therapeutic trajectories across an array of malignancies.
By harnessing the intricate biology of TIGIT and integrating it into multi-modal treatment regimens, the scientific and clinical communities stand on the cusp of a paradigm shift. This convergence of mechanistic insight and therapeutic innovation charts a promising course towards achieving durable, robust antitumor immunity, ultimately propelling the field closer to the aspirational goal of long-term cancer remission.
Subject of Research: Not applicable
Article Title: Role of TIGIT in tumor progression and immune evasion
News Publication Date: 30-Mar-2026
Web References: http://dx.doi.org/10.1097/JP9.0000000000000245
References: DOI: 10.1097/JP9.0000000000000245
Image Credits: Dr. Lei Wang and Dr. Jianwei Xu from Qilu Hospital of Shandong University, China
Keywords: TIGIT, immune checkpoint, tumor microenvironment, T cells, NK cells, regulatory T cells, cancer immunotherapy, PD-1, CD155, dendritic cells, T-cell exhaustion, immunosuppression
