Genetic and epigenetic alterations in urothelial carcinoma

Urothelial carcinoma of the bladder (UCB) is the second most common malignancy of the genitourinary tract and one of the major cancers worldwide (1). In clinical practice, UCB can be roughly classified into non-muscle-invasive bladder cancer (NMIBC) (i.e., Ta, Tis, and T1) and muscle-invasive bladder cancer (MIBC) (i.e., ≥ T2 tumors). At initial presentation, approximately 75% of the UCB tumors are diagnosed with NMIBC; however, 50–70% of them will recur and progress to MIBC (2). Thus, exploring the molecular mechanisms underpinning the development and progression of UCB are important for both accurate diagnosis and precise treatment.