Immunotherapy represents the new era of
cancer treatment because of its promising results in various
cancer types. In urological
tumors, the use of the
immune-checkpoint inhibitors (ICIs) is increasingly spreading. Although not all patients and not all diseases respond equally well to
immunotherapy, there is an increasing need to find predictive markers of response to ICIs. Patient- and
tumor-related factors may be involved in primary and secondary resistance to
immunotherapy:
tumor-derived
protein and
cytokines,
tumor mutational burden, and patient performance status and comorbidities can condition
tumor response to ICIs. Recently, some of these factors have been evaluated as potential
biomarkers of response, with conflicting results. To date, the expression of
programmed death-ligand 1 (PD-L1) and the presence of deficient mismatch repair (dMMR) in
tumor tissue are the only
biomarkers capable of guiding the clinician's decision in urothelial
cancer and
prostate cancer, respectively. In this review, we performed a comprehensive search of the main publications on
biomarkers that are predictive of response to ICIs in
urological cancers. Our aim was to understand whether existing data have the potential to drive clinical decision-making in the near future.