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Updated: Jan 7, 2026
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Tailoring In Vivo Cytotoxicity Assays to Study Immunodominance in Tumor-specific CD8+ T Cell Responses
Published on: May 6, 2019
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Inducible T-Cell Co-Stimulator (ICOS) and ICOS Ligand: Dealing With a Two-Faced Cancer Immunoregulatory System
Mina Nikanjam1, Shumei Kato1, Daisuke Nishizaki1
1Division of Hematology-Oncology, University of California San Diego, La Jolla, California, USA.
Cancer Medicine
|December 31, 2025
Summary
The inducible T-cell co-stimulator (ICOS) and its ligand (ICOSL) pathway impacts immune responses. Therapies targeting ICOS show promise, especially biomarker-driven approaches for personalized cancer treatment.
Area of Science:
- Immunology
- Oncology
- Pharmacology
Background:
- The inducible T-cell co-stimulator (ICOS) and ICOS ligand (ICOSL) pathway plays a dual role in immune stimulation and suppression.
- Expression of ICOS and ICOSL is heterogeneous across and within different cancer types.
Purpose of the Study:
- To review the mechanisms of action for ICOS and ICOSL.
- To summarize their expression patterns in cancer and other diseases.
- To outline clinical trials investigating ICOS-targeting therapies.
Main Methods:
- Literature review of ICOS and ICOSL.
- Analysis of expression patterns in various diseases.
- Summary of ongoing and completed clinical trials for ICOS-targeting agents.
Main Results:
- Both ICOS agonists and antagonists are in clinical development due to the pathway's bidirectional immune effects.
- ICOS agonists have shown limited efficacy in malignancies, potentially due to a lack of biomarker-based trials.
- An ICOS antagonist demonstrated a 44% response rate in angioimmunoblastic T-cell lymphoma, where ICOS is highly expressed on T-follicular helper cells.
Conclusions:
- Biomarker-driven strategies are crucial for personalizing ICOS-targeted combination therapies.
- Identifying which cancer patients benefit most from ICOS-directed treatments is essential.
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