Bladder caner from a perspective of 40 years

The key events leading to a better understanding of the natural history of urothelial tumors of the bladder are summarized. These were: the recognition of flat carcinoma in situ and related lesions (intraurothelial neoplasia) as principal sources of invasive cancer; identification of the unique structure of the urothelium; analysis of DNA content and the recognition of two pathways of urothelial tumors. A brief comment on the current status of immunologic and molecular genetic markers is appended.