Gefitinib is a drug used in the treatment of certain types of cancer. Acting in a similar manner to erlotinib , gefitinib selectively targets the mutant proteins in malignant cells. It is marketed by AstraZeneca and Teva under the trade name Iressa. Gefitinib is the first selective inhibitor of epidermal growth factor receptor's tyrosine kinase domain. The target protein is also sometimes referred to as Her1 or ErbB-1 depending on...