This prospective study demonstrates that a D816V-positive result in a screening blood sample identifies SM among patients with hymenoptera venom-induced anaphylaxis in whom the diagnosis would most probably have been missed, with potential severe implications.
The dysregulated tyrosine kinases, D816V KIT and FIP1L1-PDGFRA, are the prototypic oncogenic lesions resulting in systemic mastocytosis (SM) and chronic eosinophilic leukemia, respectively.
Our results show the presence of D816V KIT mutation in virtually all adults (93%) with indolent and aggressive forms of SM, except well-differentiated SM (29%), while other KIT mutations were rarely (< 3%) detected.
Control experiments showed that 10 indolent SM patients without associated MPD did not carry the JAK2 mutation V617F and that 15 CIMF patients without SM did not carry the KIT mutation D816V.
In most patients with systemic mastocytosis (SM), including aggressive SM and mast cell leukemia (MCL), neoplastic cells express the oncogenic KIT mutation D816V.
In summary, digital PCR-based KIT D816V mutation burden measurement in the tissue represents a novel biomarker with independent prognostic significance that can also be employed for monitoring disease progression and treatment response in systemic mastocytosis.
The clinical behavior of systemic mastocytosis (SM) is strongly associated with activating mutations in KIT (D816V in >80% of cases), with the severity of the phenotype influenced by additional somatic mutations, for example, in SRSF2, ASXL1, or RUNX1.
These effects were reduced by KIT inhibition or neutralization and recapitulated by enforced expression of KIT or constitutively active D816V-KIT, a gain-of-function variant associated with SM.
The discovery of KIT mutations as central to the pathobiology of mastocytosis has prompted development of KIT-targeted agents, including imatinib and midostaurin (approved medications for patients with advanced systemic mastocytosis), and drugs in development, like KIT D816V-specific inhibitor avapritinib.
In a phase I trial of avapritinib (formerly BLU-285), which targets D816V mutant KIT, for the treatment of advanced systemic mastocytosis, patients experienced rapid and durable disease control.
INNO-406 was found to inhibit proliferation in HMC-1.1 cells (IC(50): 30-40 nM), but not in HMC-1.2 cells or primary neoplastic cells in patients with KIT D816V-positive SM.
In most patients with systemic mastocytosis (SM), including aggressive SM (ASM) and mast cell (MC) leukemia (MCL), neoplastic cells express the oncogenic KIT mutation D816V, which confers resistance to imatinib.
ASqPCR for the KIT D816V mutation was a useful adjunct in helping identify those with systemic mastocytosis but not monoclonal mast cell activation syndrome.
Recent studies show that most systemic mastocytosis (SM) patients, including indolent SM (ISM) with (ISMs+) and without skin lesions (ISMs-), carry the KIT D816V mutation in PB leukocytes.
Patients with systemic mastocytosis (SM), whose MCs frequently arbor the activating D816V <i>KIT</i> mutation, may have indolent to aggressive diseases, and they may experience MC mediator related symptoms.
The identification of KIT D816V mutation and the emergence of novel targeted therapies have significantly improved the diagnosis and treatment of systemic mastocytosis.