Intended target: EGFR, ERBB2; In proteomic experiments, gefitinib interacts with several protein tyrosine kinases BRK, YES, CSK, and EPHB4, and the serine/threonine kinases RICK (RIPK2, RIP2, and CARDIAK), GAK, CaMKII, Aurora A, JNK2 and p38. Brehmer et al., Cellular targets of gefitinib. Cancer Res 65, 379-82 (2005). In AML and EGFR-expressing cells, gefitinib binds to and modulates the activity of histamine receptors (H2 and H4); Yadav et al., Epidermal growth factor receptor inhibitor cancer drug gefitinib modulates cell growth and differentiation of acute myeloid leukemia cells via histamine receptors. Biochim Biophys Acta. 1860, 2178-90 (2016).