The drug imatinib acts by inhibtion of:

Ans. is 'a' i.e. Tyrosine kinase Chronic myeloid leukemia is characterized by BCR-ABL translocationThe BCR-ABL translocation in chronic myeloid leukemia encodes a tyrosine kinase which is essential for cell proliferation and survivalImatinib (511-571) is a new molecularly targeted drug, which inhibits the tyrosine kinase activity, producing hematological and cytological remission in majority of patients.The treatment of CML has changed with the introduction of imatinib mesylate.The drug is a specifically designed inhibitor of the tyrosine kinase activity of the bcr/abl oncogene.It is well tolerated and results in nearly universal, 98% hematologic control of chronic phase disease.It has now replaced both interferon and hydroxyurea as standard therapy.The addition of either alpha interferon or low dose chemotherapy with cytarabine holds promise for even better results.Adverse effects of imatinibNauseaPeriorbital swellingRashMyalgia