The epidermal growth factor receptor(EGFR,erbB1)is a member of the erbB family of receptor tyrosine kinases(RTKs),also including erbB2/HER2,erbB3/HER3,and erbB4/HER4.1 Deregulation of EGFR signaling has been observed in many human cancers,including lung,head and neck,colorectal,ovarian,breast,and bladder cancers.Therefore,inhibitors of EGFR kinase activity may prove useful for therapeutic intervention in cancer as well as other proliferative diseases.2,3