Intratumoral expression of FoxP3-positive regulatory T-cells in T-cell lymphoma: no correlation with survival

Josefine  Lundberg; David  Berglund; Daniel  Molin; Amelie  Kinch

doi:10.1080/03009734.2018.1555195

Authors

Josefine Lundberg Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Uppsala, Sweden; Department of Medical Sciences, Section of Infectious Diseases, Uppsala University, Uppsala, Sweden
David Berglund Department of Immunology, Genetics and Pathology, Section of Clinical Immunology, Uppsala University, Uppsala, Sweden
Daniel Molin Department of Immunology, Genetics and Pathology, Section of Experimental and Clinical Oncology, Uppsala University, Uppsala, Sweden http://orcid.org/0000-0002-9646-7283
Amelie Kinch Department of Medical Sciences, Section of Infectious Diseases, Uppsala University, Uppsala, Sweden http://orcid.org/0000-0003-3420-8590

DOI:

https://doi.org/10.1080/03009734.2018.1555195

Keywords:

FoxP3, outcome, T-cell lymphoma, Tregs, tumor microenvironment

Abstract

Background. In cancer, regulatory T-cells (Tregs) were previously believed to inhibit tumor immunity, leading to reduced survival. However, in hematologic malignancies, including T-cell lymphoma (TCL), a correlation between increased numbers of tumor-infiltrating Tregs and a favorable prognosis has been reported. We aimed to investigate the expression of the Treg biomarker forkhead box protein 3 (FoxP3) in TCL in immunocompetent individuals and explore a possible correlation to overall survival.

Methods. In total, 35 diagnostic biopsies of TCL were stained using a FoxP3-specific monoclonal antibody (clone 236A/E7). Visual scoring was performed by counting positive cells in 15 high-power fields. Clinical data were collected retrospectively from medical records.

Results. All the TCLs contained FoxP3⁺ cells, median 342 FoxP3⁺ cells/mm² (range 1–3047). The degree of intratumoral expression of FoxP3 varied between the different subtypes of TCL, with the highest frequency found in angioimmunoblastic TCL. The frequency of intratumoral FoxP3⁺ cells had no impact on overall survival; neither when using a cutoff value of 200 FoxP3⁺ cells/mm² (P = 0.84) nor with FoxP3 as a continuous variable (P = 0.63).

Conclusions. Intratumoral Tregs are frequently found in TCL in immunocompetent individuals. In this heterogeneous group of TCL, there was no correlation between the density of intratumoral FoxP3⁺ cells and overall survival.