BLADDER CARCINOMAS AND NORMAL UROTHELIUM UNIVERSALLY EXPRESS GP200-MR6, A MOLECULE FUNCTIONALLY ASSOCIATED WITH THE INTERLEUKIN-4 RECEPTOR (CD-124)

Monoclonal antibody MR6 detects gp200-MR6, a molecule functionally ass ociated with the interleukin 4 (IL-4) receptor. Positive immunolabelli ng with MAb MR6 was obtained in 28/28 transitional cell carcinomas of the bladder, representing a range of different grades and stages of di sease, as well as in all control non-neoplastic urothelia. The express ion of mutant p53 protein and epidermal growth factor receptor was det ected in 14/28 and 20/28 cases respectively. Proliferation indices, de termined by Ki67 labelling, ranged from 5% to 95% among these tumours. The universal expression of gp200-MR6 in neoplastic and nonneoplastic urothelium has important implications for the possible use of IL-4 in tumour therapy and suggests that IL-4 may play a role in differentiat ion and homeostasis of urothelium and other mucosal epithelia.