Clonal analysis of human recurrent superficial bladder cancer by immunohistochemistry of P53 and retinoblastoma proteins.

Abstract

To investigate the clonal origin of malignant cells in recurrent superficial bladder cancer. We compared the protein expression of p53 and retinoblastoma (Rb) by immunohistochemistry using antibody P1801 and PMG3-245, respectively, in 13 patients at the time of primary superficial bladder cancer resection (6 Ta and 7 T1) and their 15 corresponding recurrences of disease. Mutations in p53 and Rb were inferred on the basis of immunoperoxidase staining. At the time of initial tumor resection, a p53 mutation was observed in 5 patients (39%) and an Rb mutation was observed in 3 (23%). The p53/Rb mutation status of recurrent bladder cancers completely matched their corresponding primary bladder cancer. The chance that recurrent bladder cancer originated from independent clones in this study was extremely small (p < 10(-6)). This result strongly supports the monoclonal origin of recurrent superficial bladder cancer.