Iranian Journal of Pathology

Harnessing Tumor-Infiltrating Lymphocytes for Improved Cancer Outcomes

Document Type : Letters to the Editor

Authors

Gunvanti Rathod 1
Pragnesh Parmar 2

1 Department of Pathology, AIIMS, Bibinagar, Telangana, India

2 Department of FMT, AIIMS, Bibinagar, Telangana, India

https://doi.org/10.30699/ijp.2025.2068603.3502
Abstract
Tumor-infiltrating lymphocytes (TILs) form a pivotal part of the immune system’s defense against cancer, and their density, composition, and spatial distribution reflect both tumor biology and the degree of host immune activation. Across multiple carcinoma types—including breast, lung, colorectal, ovarian, and head and neck cancers—recent clinical studies and meta-analyses have shown that high levels of TILs, especially CD8⁺ cytotoxic T cells, are consistently linked with improved prognosis and enhanced responsiveness to chemotherapy and immune checkpoint inhibitors. Standardized assessment tools, such as the Immunoscore in colorectal carcinoma and stromal TIL evaluation guidelines in breast cancer, have improved reproducibility and clinical relevance. TILs not only act as prognostic and predictive biomarkers but are also being harnessed as therapeutic agents in emerging immunotherapy strategies, including adoptive cell therapy. Despite these advances, variability in evaluation methods and the functional heterogeneity of TIL subsets remain challenges. Standardization of assessment protocols and deeper characterization of TIL phenotypes will be essential to fully integrate these immune markers into routine oncology practice and optimize their potential in precision medicine.

Keywords

Tumor-infiltrating lymphocytes
Carcinoma
Immunotherapy
CD8 T cells
Prognostic biomarkers

Subjects

Copyright © 2026. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The license also allows users to adapt, remix, transform, and build upon the material for any purpose, including commercial use.

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Iranian Journal of Pathology
Volume 21, Issue 1
Winter 2026
Pages 143-145

  • Receive Date 11 August 2025
  • Accept Date 03 September 2025

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