EGFR and central nervous system cancer: This resulting receptor, known as the de2-7 EGFR, does not bind ligand but displays a low level of constitutive activity and imparts a significant in vivo growth advantage to a number of tumour types including the breast, lung and particularly gliomas (Nishikawa et al, 1994; Wikstrand et al, 1998; Tang et al, 2000).