Mast-cell leukemia

Mast cell leukemia (MCL), the leukemic manifestation of systemic mastocytosis (SM), is characterized by leukemic expansion of immature mast cells (MCs) in the bone marrow (BM) and other internal organs; and a poor prognosis. Gain-of-function mutations in the proto-oncogene c-kit that induce constitutive kinase activity of its product, KIT protein, are characteristic of various neoplastic diseases including MCL. Downstream signaling pathways, including PI3 kinase (PI3K)/AKT, are inappropriately activated, and this is believed to contribute to the abnormal proliferation and survival of these neoplastic cells. The reason of poor prognosis of MCL patients is mostly that MCs in these patients are largely resistant against conventional drugs and targeted drugs, including tyrosine kinase inhibitors (TKI) directed against KIT D816V such as PKC412 (midostaurin).