Tumor Infiltrating CD8+ and Foxp3+ Lymphocytes Correlate to Clinical Outcome and Human Papillomavirus (HPV) Status in Tonsillar Cancer

Anders Näsman,Mircea Romanitan,Linda Marklund,Torbjörn Ramqvist,Hemming Johansson,Cecilia Nordfors,Nathalie Grün,Eva Munck-Wikland,Lalle Hammarstedt,Tina Dalianis,Joseph Califano

doi:10.1371/journal.pone.0038711

Abstract

BackgroundHuman papillomavirus (HPV) is a causative factor for tonsillar squamous cell carcinoma (TSCC) and patients with HPV positive (HPV+) TSCC have a better clinical outcome than those with HPV negative (HPV−) TSCC. However, since not all patients with HPV+TSCC respond to treatment, additional biomarkers are needed together with HPV status to better predict response to therapy and to individualize treatment. For this purpose, we examined whether the number of tumor infiltrating cytotoxic and regulatory T-cells in TSCC correlated to HPV status and to clinical outcome.MethodsFormalin fixed paraffin embedded TSCC, previously analysed for HPV DNA, derived from 83 patients, were divided into four groups depending on the HPV status of the tumor and clinical outcome. Tumors were stained by immunohistochemistry and evaluated for the number of infiltrating cytotoxic (CD8+) and regulatory (Foxp3+) T-cells.ResultsA high CD8+ T-cell infiltration was significantly positively correlated to a good clinical outcome in both patients with HPV+ and HPV- TSCC patients. Similarly, a high CD8+/Foxp3+ TIL ratio was correlated to a 3-year disease free survival. Furthermore, HPV+TSCC had in comparison to HPV−TSCC, higher numbers of infiltrating CD8+ and Foxp3+ T-cells.ConclusionsIn conclusion, a positive correlation between a high number of infiltrating CD8+ cells and clinical outcome indicates that CD8+ cells may contribute to a beneficial clinical outcome in TSCC patients, and may potentially serve as a biomarker. Likewise, the CD8+/Foxp3+cell ratio can potentially be used for the same purpose.

Highlights

Recent studies from Europe and the US have reported an increase in the incidence of oropharyngeal squamous cell carcinoma (OSCC), for tonsillar squamous cell carcinoma (TSCC)
Whereas Human papillomavirus (HPV) associated tumors, including HPV positive (HPV+)TSCC are driven by viral oncogenes, e.g. E6 and E7, and have fewer cellular mutations, HPV2TSCC develop by accumulation of genetic changes mainly caused by environmental factors such as smoking [9]
The purpose of this study was to examine the presence of tumor infiltrating CD8+ and Foxp3+ T-cells in TSCC in relation to clinical outcome and tumor HPV status, and to establish if these tumor infiltrating lymphocytes (TILs) can potentially be used in the clinic as biomarkers either alone, or together with the HPV status of the tumor to predict clinical outcome

Summary

Introduction

Recent studies from Europe and the US have reported an increase in the incidence of oropharyngeal squamous cell carcinoma (OSCC), for tonsillar squamous cell carcinoma (TSCC). Tumor specific T-cells are detected in most cervical cancer patients, at low and insufficient levels [11,12] and the presence of tumor infiltrating lymphocytes (TILs) has been linked to a better prognosis [13,14]. Since not all patients with HPV+TSCC respond to treatment, additional biomarkers are needed together with HPV status to better predict response to therapy and to individualize treatment For this purpose, we examined whether the number of tumor infiltrating cytotoxic and regulatory T-cells in TSCC correlated to HPV status and to clinical outcome

Objectives

Methods

Results

Discussion

Conclusion