AUTHOR=Lo Presti Elena , Pizzolato Gabriele , Corsale Anna Maria , Caccamo Nadia , Sireci Guido , Dieli Francesco , Meraviglia Serena 

TITLE=γδ T Cells and Tumor Microenvironment: From Immunosurveillance to Tumor Evasion

JOURNAL=Frontiers in Immunology

VOLUME=Volume 9 - 2018

YEAR=2018

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.01395

DOI=10.3389/fimmu.2018.01395

ISSN=1664-3224

ABSTRACT=gamma delta  T cells possess cytotoxic anti-tumor activity mediated by production of pro-inflammatory cytokines, direct cytotoxic activity and regulation of the biological functions of other cell types. Hence, these features  have prompted the development of therapeutic strategies in which gamma delta T cells- agonists or ex vivo-expanded gamma delta T cells are administered to tumor patients. 
Several studies have shown that gamma delta  T cells are an important component of tumor-infiltrating lymphocytes in patients affected by different types of cancer and a recent  analysis of ~18,000 transcriptomes from 39 human tumors  identified tumor-infiltrating gamma delta T cells as the most significant favourable cancer-wide prognostic signature.
However, the complex and intricate interactions between tumor cells, tumor microenvironment  and  tumor-infiltrating immune cells  results in a balance between tumor-promoting and tumor-controlling effects and gamma delta T cells functions are often diverted or impaired  by immunosuppressive signals originating from the tumor microenvironment.
This review focuses on the dangerous liason between gamma delta T cells and tumoral microenviroment and raises the possibility that strategies capable to reduce the immunosuppressive  environment and increase the cytotoxic ability  of gamma delta T cells may be the key factor to improve their utilization in tumor immunotherapy.