Elevated expression of the interleukin 4 receptor in carcinoma: a target for immunotherapy?

Studies using monoclonal antibody MR6, which is thought to bind to the interleukin-4 growth factor receptor (IL-4R), indicate that IL-4R molecules are upregulated in tumours of epithelial origin and that radiolabelled MR6 is effective as an in vivo tumour imaging agent. Immunohistochemical analysis of a wide range of solid tumours using monoclonal antibody MR6 has demonstrated elevated expression of the IL-4R on a variety of carcinomas. The equivalent normal tissue showed either weak or no expression of this molecule. No other tumours studied were positive. The molecular weight of the receptor on tumour cells was indistinguishable from that on normal tissue. These data raise the possibility that the IL-4R is the product of a novel oncogene such that elevated expression of this growth factor receptor could be involved in the process of carcinogenesis. Monoclonal antibodies to the IL-4R, such as MR6, may therefore be useful reagents not only for diagnosis and immunoscintigraphy, but also for in vivo antibody-guided therapy of epithelial cancers.