Protein kinases play essential roles in the regulation of cell proliferation. Point mutations or/and fusions of protein kinases are frequently identified in human cancers, and targeting such activated kinases provides us with a chance to eradicate tumor cells. This was first proved by imatinib mesylate that inhibits ABL tyrosine kinase and, thereby, efficiently kills malignant cells in chronic myeloid leukemia. In addition, other clinical trials are ongoing for kinase inhibitors against EML4--ALK in lung cancer, JAK2 in myeloproliferative disorders and BRAF in malignant melanoma. Early reports indeed reveal that such targeting compounds are promising drugs for human cancers with activated kinases.