The immune infiltrate in prostate, bladder and testicular tumors: Beyond the Abstract

The importance of immune surveillance in controlling neoplastic cells growth and progression has been known for decades. Immunotherapy with BCG has been used for a long time in non-muscle invasive bladder cancer with a significant control but incomplete of this disease. Accumulating evidence showed a correlation between tumor infiltrating lymphocytes (TILs) and outcome in a variety of tumors.

An immune phenotype has also been associated with benefit from immunotherapy with the newest agents targeting inhibitory immune checkpoint molecules that are advancing the treatment of several aggressive neoplastic diseases. In genito-urinary tumors, their use has been associated with a clear benefit in advanced urothelial bladder cancer and kidney cancer and currently several trials are ongoing on early stages of the diseases. 

Despite the clinical efficacy and the durable responses to immune checkpoint blockade, only a proportion of patients benefit from this treatment approach. Currently, several potential predictive biomarkers are under evaluation for optimizing patients’ selection. Of note, in non-small cell lung cancer the expression of PD-L1 is being used as a selection criterion for immunotherapy with pembrolizumab, an anti-PD-1 as a first and second line agent. In genito-urinary cancers, no predictive biomarkers exist for use in clinical practice. 

Our review focused on the role of TILs in prostate, bladder and testicular cancers. Most of the evidence came from retrospective studies and few prospective trials ongoing. Therefore, further investigations are needed to clarify whether the assessment of TILs would have a prognostic and/or predictive significance in these specific diseases. 

In addition to TILs, there are many molecular factors which are also under investigation as prognostic and/or predictive factors. PD-L1 expression, immune gene signature, IL-8 and mutation burden are among these factors. A combination of several factors (immunogram) might be more pertinent than individual parameter and this approach is under investigation.

Written By: Cinzia Solinas, MD, Molecular Immunology Unit, Université Libre de Bruxelles, Institut Jules Bordet, Brussels, Belgium;  Nieves Martinez Chanzá, Medical Oncology, Université Libre de Bruxelles, Erasme Hospital, Brussels, Belgium;  Ahmad Awada, MD, PhD, Medical Oncology, Université Libre de Bruxelles, Institut Jules Bordet;  Mario Scartozzi, MD, PhD, Medical Oncology, University of Cagliari, Cagliari, Italy

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