The
stem cell factor (SCF)
c-kit receptor interaction plays a critical role in the development and survival of mast cells. Several studies have also associated
c-kit receptor mutations with the human diseases,
mastocytosis and
piebaldism. Overexpression of c-kit has been reported to be associated with
myeloproliferative disorders and
myelodysplastic syndromes. Using peripheral blood mononuclear cells (PBMCs) from 11 patients with indolent
mastocytosis (category I),
mastocytosis with an associated hematologic disorder (category II), or aggressive
mastocytosis (category III); a patient with CMML unassociated with
mastocytosis, and PBMCs from 13 normal subjects, we examined the level of expression of c-kit
mRNA along with other c-kit
isoforms to determine if overexpression of the
c-kit receptor was associated with
mastocytosis. Using quantitative competitive PCR, c-kit
mRNA levels on average were found to be statistically elevated in the five patients with
mastocytosis with an associated hematologic disorder and in the patient with aggressive
mastocytosis as compared with controls, but not elevated in patients with indolent
mastocytosis. The relative
mRNA expression for the two c-kit
isoforms was not significantly different in the
mastocytosis patients compared with controls. This demonstration of the overexpression of c-kit
mRNA in
mastocytosis, and particularly those patients with clinical evidence of
myelodysplastic syndrome, adds evidence to support the conclusion that
mastocytosis, at least in some patients, is a feature of myelodysplasia; and suggests that determination of c-kit
mRNA expression in PBMCs may provide an additional approach to assessing prognosis.