Asp-816-->Val with a subset of sporadic persistent (systemic) mastocytosis (mostly adults), and Gly-839-->Lys with (a subset of) typical pediatric (mostly cutaneous) mastocytosis.
A case of systemic mastocytosis carrying the characteristic mutation at codon 816 (D816V) in the KIT gene of mast cells, with two concurrent accompanying clonal haematopoietic non-mast cell-lineage disorders, chronic myeloproliferative disease, unclassifiable and precursor B lymphoblastic leukaemia is documented.
Although hymenoptera-induced anaphylaxis is not primarily a mast cell-driven hematological disorder, the latter is present in a significant proportion of patients and has to be excluded by basal serum tryptase determination, skin inspection as well as exclusion of systemic mastocytosis by D816V mutation analysis in peripheral blood and/or bone marrow examination in selected patients.
ASqPCR for the KIT D816V mutation was a useful adjunct in helping identify those with systemic mastocytosis but not monoclonal mast cell activation syndrome.
Because the D816V mutation was detected in the initial bone marrow specimen, strict application of three minor diagnostic criteria (spindling, CD25, D816V) enabled a diagnosis of SM-AML to be confirmed retrospectively in the initial bone marrow tissue.
Bone marrow (BM) histology/immunohistochemistry, KIT D816V mutation analysis and serum tryptase measurements are mandatory tools for diagnosis of systemic mastocytosis (SM).
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.
DCC-2618 is a spectrum-selective pan KIT and PDGFRA inhibitor which blocks KIT D816V and multiple other kinase targets relevant to systemic mastocytosis.
Expression of activated STAT5 in neoplastic mast cells in systemic mastocytosis: subcellular distribution and role of the transforming oncoprotein KIT D816V.
GEP analyses were performed by using DNA-oligonucleotide microarrays in highly purified BMMCs from patients with SM carrying the D816V KIT mutation (n=26) classified according to the diagnostic subtype of SM versus normal/reactive BMMCs (n=7).
Here we investigated IL1β, IL6, IL13, CCL23 and clusterin plasma levels in 75 SM patients--66 indolent SM (ISM) and 9 aggressive SM--and analyzed their prognostic impact among ISM cases grouped according to the extent of hematopoietic involvement of the bone marrow cells by the KIT D816V mutation.
Here, the authors report significant symptomatic, cutaneous and systemic response to imatinib in a case of childhood onset indolent D816V KIT unmutated systemic mastocytosis (SM).
In a majority of all patients with systemic mastocytosis (SM) including those with mast cell leukemia (MCL), neoplastic mast cells (MC) display the D816V-mutated variant of KIT.
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.
In addition, EXEL-0862 induced a time- and dose-dependent proapoptotic effect in both mast cell lines and caused a significant reduction in mast-cell content in bone marrow samples from patients with SM harboring D816V and from those without the D816V mutation.
In both conditions, an aberrantly activated oncoprotein with tyrosine kinase activity, namely BCR-ABL1 in chronic myeloid leukemia, and mutant KIT, mostly KIT D816V, in systemic mastocytosis, is key to disease evolution.
In conclusion, KIT D816V mutation sensitized MC to HDACi mediated killing, and SAHA may be of value as specific treatment for SM, although the specific mechanism of action requires further investigation.