The present invention relates to a novel form of human EGFR found in certain tumors and conditions. The protein is termed here mLEEK, and the cDNA that encodes it has also been isolated. The mLEEK protein is capable of efficiently inducing the transcription of multiple genes resulting in various physiologic processes. Antibodies directed against the protein can be used for improving the diagnosis of diseases or for the treatment of diseases. The protein itself can be directly used or blocked for therapeutic purposes. Nucleic acid based probes or PCR primers specific for the mLEEK sequence can be used for diagnostic purposes. Inhibitory nucleic acid based molecules, such as antisense, siRNA, or shRNA, may be used for therapeutic purposes. The mLEEK sequence is essentially formed by the skipping of exons 2 through 22 in the EGF receptor gene leading to a fusion of exon 1 to exon 23. Other mutants are disclosed, which include the fusion of exon 1 to exon 24 and the fusion of exons 1 to exon 28.
