... and small-molecule tyrosine kinase inhibitors, such as gefitinib and erlotinib, whichtarget the intracellular tyrosine kinase domain of the EGFR. Furthermore,recent clinical and laboratory studies ... compete with ATP for binding to the tyrosine kinase pocket of the receptor, therebyinhibiting receptor tyrosine kinase activity and EGFRsignaling pathways (Fig. 1). Early clinical studiesshowed ... off and the cancer cells undergoing apoptosis.Moreover, EGFR mutations result in repositioning ofcritical residues surrounding the ATP-binding cleft of the tyrosine kinase domain of the receptor...