Bladder cancer is a type of cancer that begins in the cells of the bladder, the organ responsible for storing urine. It is one of the most common cancers affecting the urinary system and can occur at any age, although it is more prevalent in older adults. Bladder cancer typically develops in the inner lining of the bladder (urothelial cells), but it can also originate from other types of cells in the bladder. Smoking, exposure to certain chemicals, chronic bladder inflammation, and genetic factors are known risk factors for bladder cancer.