Receptor for interleukin 13 is a marker and therapeutic target for human high-grade gliomas

Glioblastoma multiforme (GBM) is an incurable brain tumor. Due to the strik ing heterogeneity that characterizes GEM, there is no known tumor-specific antigen or receptor that is expressed by a majority of GEM patients. We fou nd that virtually all studied human GEM specimens (23 samples) abundantly e xpressed a receptor for interleukin (IL)-13 in situ, whereas normal human b rain had few, if any, IL-13-binding sites. The GEM-associated IL-13 recepto r was both quantitatively and qualitatively different from and, thus, more restrictive than the shared signaling receptor of normal tissue: it was IL- 4 independent. The receptor for IL-13 was overexpressed by a majority of ca ncer cells in situ, Furthermore, cytotoxins targeted to this more restricti ve IL-13R produced cures in animals bearing xenografts of human high-grade gliomas, Thus, unexpectedly, the receptor for an immune regulatory cytokine may be a long sought marker and, concomitantly, a unique imaging site and therapeutic target for GEM, the most malignant and the most heterogeneous o f brain tumors.