Fig. 1.

Overview of clinical examination methods for bladder cancer and laboratory analytical techniques for liquid biopsies. Routine imaging tests used for bladder cancer detection and diagnosis include X-ray, CT, and PET–CT. Cystoscopy and tissue biopsy are the gold standard for the diagnosis of bladder cancer. Urine cytology is available as a complementary test. Liquid biopsy is emerging as a promising method. Liquid biopsy involves the collection and analysis of five different tumor components from peripheral blood samples: CTCs, cell-free nucleic acids (cfDNA/ctDNA, cfRNA), exosomes, and metabolomics and proteomics. Tumor components are then captured and analyzed in peripheral blood samples using appropriate laboratory assays. CT computed tomography, PET positron emission computed tomography, CTCs circulating tumor cells, ctDNA circulating tumor deoxyribonucleic acid, cfDNA cell-free DNA, cfRNA cell-free RNA