Bladder cancer is a type of cancer that begins in the cells of the bladder, which is the organ that stores urine. It often presents with symptoms such as blood in the urine, frequent urination, and pain during urination. Risk factors include smoking, exposure to certain chemicals, and chronic bladder infections. There are different types of bladder cancer, with the most common being urothelial carcinoma. Diagnosis typically involves urine tests, imaging studies, and a biopsy. Treatment options may include surgery, chemotherapy, and immunotherapy, depending on the stage and grade of the cancer.