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Background: Research of biomarkers in genitourinary tumors goes along with the development of complex emerging techniques ranging from next generation sequencing platforms, applied to archival pathology specimens, cytological samples, liquid biopsies, and to patient-derived tumor models., Methods: This contribution is an update on molecular biomarkers for diagnosis, prognosis and prediction of response to therapy in genitourinary tumors. The following major topics are dealt with: Immunological biomarkers, including the microbiome, and their potential role and caveats in renal cell carcinoma, bladder and prostate cancers and testicular germ cell tumors; Tissue biomarkers for imaging and therapy, with emphasis on Prostate-specific membrane antigen in prostate cancer; Liquid biomarkers in prostate cancer, including circulating tumor cell isolation and characterization in renal cell carcinoma, bladder cancer with emphasis on biomarkers detectable in the urine and testicular germ cell tumors; and Biomarkers and economic sustainability., Conclusion: The identification of effective biomarkers has become a major focus in cancer research, mainly due to the necessity of selecting potentially responsive patients in order to improve their outcomes, as well as to reduce the toxicity and costs related to ineffective treatments., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Immune checkpoint inhibitors have revolutionized the treatment of many malignancies with over a dozen new United States Food and Drug Administration (FDA) approvals in the past six years. Due to the combination of potent treatment success and potentially deadly adverse effects from immune checkpoint inhibitors, gathering prognostic and predictive information about FDA-indicated tumors is prudent., Method: PD-L1 expression is a poor prognostic factor and predictive of better responses from both PD-1 and PD-L1 inhibitors in a variety of tumor types including Renal Cell Carcinoma (RCC) and urothelial carcinoma. Each FDAapproved PD-1/PD-L1 drug is paired with a PD-L1 Immunohistochemistry (IHC) assay. The majority of PD-1/PDL1 inhibitor clinical trials use proprietary IHC antibodies with undefined validation data. Thus, there is need for improved knowledge and application of PD-1/PD-L1 IHC biomarkers. There is a wealth of recent publications using antibody clones to characterize tumor PD-1/PD-L1 expression profiles., Results: PD-1 is expressed on lymphocytes. PD-L1 is expressed on both tumor cells and immune cells. IHC staining appears in membranous fashion. A cutoff of at least 5% tumor cell PD-L1 staining for positivity has worked for most studies. Caution should be observed when employing tissue microarray techniques., Conclusion: RCC has been the most studied of the genitourinary malignancies for PD-L1 expression. The atezolizumab- approved IHC assay is unique in that only immune cell staining is quantified for the use of this assay in urothelial carcinoma. With familiarity of the current FDA guidelines, published medical literature, and general immunohistochemical considerations, the use of immune checkpoint biomarkers can continue to flourish., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)