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Query: EC:2.7.10.1 (
ERK
)
95,504
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract. Recently, we found that GISTs expressed
KIT
, a receptor tyrosine kinase encoded by the protooncogene
c-kit
. We propose that GISTs may originate from interstitial cells of Cajal (ICCs), which are considered to be pacemaker cells for the autonomous movement of the gastrointestinal tract. There are major two reasons for this proposal: one is that both GISTs and ICCs are double-positive for
KIT
and CD34, and the other is that multiple GISTs appear to develop from diffuse ICC hyperplasia in germline mutations of the
c-kit
gene. Because somatic gain-of-function mutations of the
c-kit
gene are observed in solitary GISTs, and because the germline gain-of-function mutations of the
c-kit
gene are observed in familial and multiple GISTs, the gain-of function mutations of the
c-kit
gene are considered to be a cause of the development of GISTs.
...
PMID:Gastrointestinal stromal tumors: their origin and cause. 1170 20
In cultures, and in tissues as well, Hodgkin's and Reed-Sternberg (H-RS) cells and anaplastic large cell lymphoma (ALCL) cells are known to express a variety of cytokines, including IL-1, -5, -6, -8, -9, TNF-alpha, GM-CSF, M-CSF, TGF-beta, CD70, CD80, and CD86. Various numbers of H-RS/ALCL cells may express cytokine receptors (R), such as CD30, CD40, IL-2R (CD25/CD122), IL-6R (CD126), IL-7R (CD127), TNF-R (CD120), TGF-beta-R (CD 105/endoglin), M-CSF-R (
CD115
), and SCF-R (CD117/
c-kit
receptor). All of these cytokines and cytokine receptors are implicated in the growth regulation of H-RS/ALCL cells, the histopathologic alterations in tissues, and the clinical manifestations in patients with Hodgkin's disease (HD) or ALCL. Many of these cytokines or cytokine receptors also play an important role in the pathogenesis of other types of lymphomas. In this review, we describe the cytokine or cytokine-receptor expression that is diacritic for H-RS/ALCL cells. The identification of such unique cytokine-cytokine receptor interactions is likely to explain the biologic property that distinguishes HD/ALCL from other types of lymphomas. These interactions include those of CD30L-CD30, CD40L-CD40, CD70-CD27, CD80/CD86- CD28, SCF-CD117, IL-9-IL-9R, and IL-7-IL-7R. The H-RS/ALCL cells express IL-9 and two cytokine receptors, CD30 and CD117, which are observed infrequently in NHLs. Although IL-7 expression is not restricted to H-RS/ALCL cells, the expression of IL-7 in conjunction with IL-9 and/or CD117 may be regarded as unique for HD/ALCL because of an unusual combination and a synergistic activity among these cytokines. The expression of CD70 and CD80/CD86 (as cytokines) may exert a unique effect in HD because of intimate contact between H-RS cells and CD27/CD28-positive T cells. The expression of these costimulators (CD70 and CD80/CD86) and other adhesion/constimulator molecules such as CD54 and CD58, along with the secretion of soluble cytokines such as IL-1, IL-6, IL-7, or TNFs by H-RS/ALCL cells, could result in the profound T-cell proliferation often seen in lymph nodes involved by HD and some ALCL. On the other hand, the expression of CD30L and CD40L by surrounding T cells may affect the proliferation of H-RS/ALCL cells. The cytokine-cytokine receptor interaction between H-RS cells and T cells via direct cell-cell contact is bidirectional, a situation not commonly seen in NHLs. Copyright 1995 S. Karger AG, Basel
...
PMID:Hodgkin's Disease and Anaplastic Large Cell Lymphoma Revisited. 1. unique cytokine and cytokine receptor profile distinguished from that of non-hodgkin's lymphomas. 1172 67
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. These tumors span a wide clinical spectrum from benign to malignant and have long been recognized for their nearly absolute resistance to chemotherapy and radiation treatment. Surgery is the primary treatment modality for GISTs, but GISTs represent an incurable malignancy for patients with metastatic or unresectable disease. Thus, novel approaches to the treatment of GISTs were desperately needed. Gastrointestinal stromal tumors are characterized by expression of the transmembrane receptor tyrosine kinase
KIT
, which is defined by the CD117 antigen and is the product of the
c-kit
proto-oncogene. Activating or gain-of-function mutations in the
c-kit
gene have been identified in the majority of GIST cases. The resulting constitutive
KIT
tyrosine kinase activity was hypothesized to provide growth and survival signals to GIST cells and to be crucial to the pathogenesis of the disease. This hypothesis became testable with the identification of the signal transduction inhibitor imatinib mesylate (formerly STI571, [Gleevec]; Novartis Pharmaceuticals Corp, East Hanover, NJ), which blocks the tyrosine kinase activity of
KIT
as well as the kinase activity of the normal c-abl gene product, the oncogenic Bcr-Abl chimeric fusion protein of chronic myeloid leukemia, and the platelet-derived growth factor receptor. Preclinical experiments showed rapid inhibition of ligand-independent
KIT
phosphorylation, decreased cellular proliferation, and induction of apoptosis after exposure of GIST cells to imatinib mesylate in vitro. These results provided the rationale to move forward with clinical testing of imatinib mesylate as an anticancer therapy for GIST. In early 2000, a dramatic clinical and radiographic response to imatinib mesylate was shown in a single patient with advanced, chemotherapy-resistant GIST. The powerful scientific rationale for this proof-of-concept study, together with the durable and significant response observed in this first GIST patient treated with imatinib mesylate, have provided the driving force for rapid clinical development of this targeted therapy in this solid tumor indication.
...
PMID:Targeting c-kit mutations in solid tumors: scientific rationale and novel therapeutic options. 1174 Aug 3
Here, we report that the number of CD11c(+)CD3(-) B220(-) cells increases in autoimmune-prone male (NZW x BXSB)F1 (W/BF1) mice with age. The CD11c(+)CD3(-)B220(-) cells from W/BF1 mice show a typical stellate shape and induce the proliferation of T cells. In the CD11c(+)CD3(-)B220(-) cells from W/BF1 mice, CD11b (Mac-1alpha), NK 1.1, and CD95 (Fas) are upregulated in comparison with normal mice, while the expression of CD8alpha, CD117 (
c-kit
),
CD135
(Flk-2/Flt-3), and Sca-1 decreases. There is a significant increase in Flt-3L (FL) mRNA in the bone marrow of W/BF1 mice with age. Moreover, activated hemopoietic cells express high levels of FL. The injection of CD11c(+)CD3(-)B220(-) cells from old W/BF1 mice to young W/BF1 mice transiently induces autoimmune disease (thrombocytopenia). These results suggest that hyperproduction of FL from activated hemopoietic cells induces a dramatic increase in the number of dendritic cells in aged W/BF1 mice, followed by the acceleration of autoimmunity.
...
PMID:Marked increase in number of dendritic cells in autoimmune-prone (NZW x BXSB)F1 mice with age. 1179 23
Mutations in
KIT
encoding the
mast/stem cell growth factor receptor
(
MGF
) are responsible for coat color variation in domestic pigs. The dominant white phenotype is caused by two mutations, a gene duplication and a splice mutation in one of the copies leading to skipping of exon 17. Here we applied minisequencing and pyrosequencing for quantitative analysis of the number of copies with the splice form. An unexpectedly high genetic diversity was revealed in white pigs. We found four different
KIT
alleles in a small sample of eight Large White females used as founder animals in a wild boar intercross. A similar number of
KIT
alleles was found in commercial populations of white Landrace and Large White pigs. We provide evidence for at least two new
KIT
alleles in pigs, both with a triplication of the gene. The results imply that
KIT
alleles with the duplication are genetically unstable and new alleles are most likely generated by unequal crossing over. This study provides an improved method for genotyping the complicated Dominant white/
KIT
locus in pigs. The results also suggest that some alleles may be associated with negative pleiotropic effects on other traits.
...
PMID:Unexpectedly high allelic diversity at the KIT locus causing dominant white color in the domestic pig. 1180 65
Glomus tumors usually occur in the peripheral soft tissues, but similar tumors have also been reported in the stomach and occasionally in the intestines. However, the relationship of these tumors to peripheral glomus tumors and gastrointestinal stromal tumors has not been fully clarified because previous series of gastrointestinal glomus tumors predate availability of immunohistochemistry. This clinicopathologic study examined 32 gastrointestinal glomus tumors. All but one of the tumors were located in the stomach and the remaining tumor was from the cecum. The tumors occurred with a strong female predominance (23 females and 9 males) and a median age of 55 years (range 19-90 years). The gastric tumors typically presented with gastrointestinal bleeding or ulcer-like symptoms, and 14 tumors had mucosal ulceration. Five tumors were incidental findings. The tumor sizes varied from 1.1 to 7 cm (median 2 cm), and most were located in the antrum. Histologically, the tumors typically had a solid pattern of sharply demarcated, round glomus cells with prominent, mildly dilated pericytoma-like vessels. Vascular invasion and focal atypia were relatively common (seen in 11 and 13 cases, respectively), and low mitotic activity (1-4 per 50 high power fields), was seen in 10 cases. Immunohistochemically, all tumors were positive for alpha-smooth muscle actin and calponin, and nearly all had a net-like pericellular laminin and collagen type IV positivity. All tumors were negative for desmin and S-100 protein. Three tumors had focal synaptophysin positivity, but none was positive for chromogranin. All tumors lacked
KIT
expression and the GIST-specific mutations in the
c-kit
gene. Follow-up revealed one patient death of metastatic disease to liver at 50 months; this tumor had 1 mitosis per 50 high power fields, but had spindle cell foci, mild atypia, and vascular invasion. Thirteen patients were well and alive after long-term follow-up. Gastrointestinal glomus tumors occur almost exclusively in the stomach, and they have a good overall prognosis, but a small, unpredictable potential for malignant behavior exists. These tumors are phenotypically similar to peripheral glomus tumors and differ from epithelioid GISTs.
...
PMID:Gastrointestinal glomus tumors: a clinicopathologic, immunohistochemical, and molecular genetic study of 32 cases. 1185 1
Mast cells are thought to participate in a variety of immune responses, such as parasite resistance and the allergic reaction. Mast cell development depends on stem cell factor (Kit ligand) and its receptor,
c-Kit
. Gab2 is an adaptor molecule containing a pleckstrin homology domain and potential binding sites for SH2 and SH3 domains. Gab2 is phosphorylated on tyrosine after stimulation with cytokines and growth factors, including KitL. Gab2-deficient mice were created to define the physiological requirement for Gab2 in KitL/
c-Kit
signaling and mast cell development. In Gab2-deficient mice, the number of mast cells was reduced markedly in the stomach and less severely in the skin. Bone marrow-derived mast cells (BMMCs) from the Gab2-deficient mice grew poorly in response to KitL. KitL-induced
ERK
MAP kinase and Akt activation were impaired in Gab2-deficient BMMCs. These data indicate that Gab2 is required for mast cell development and KitL/
c-Kit
signaling.
...
PMID:Requirement of Gab2 for mast cell development and KitL/c-Kit signaling. 1186 9
The stem cell factor/
c-kit
tyrosine kinase receptor pathway has been shown to be important for tumor growth and progression in several cancers, including mast cell diseases, gastrointestinal stromal tumor, acute myeloid leukemia, small cell lung carcinoma, and Ewing sarcoma. Studies using the oral agent STI-571 (Gleevec, Novartis), an inhibitor of the tyrosine kinases bcr-abl,
c-kit
, and
PDGFR
, have shown significant responses in patients with chronic myelogenous leukemia and gastrointestinal stromal tumor. With the aim of identifying additional groups of tumors that may use the stem cell factor/
c-kit
pathway and secondarily may be responsive to STI-571 treatment, this study surveyed 151 primary tumors from patients treated at St. Jude Children's Research Hospital for immunohistochemical expression of
c-kit
. Formalin-fixed, paraffin-embedded sections were stained with rabbit polyclonal anti-human
c-kit
(CD117, Dako) using standard avidin-biotin-peroxidase complex technique, antigen retrieval, and an automated stainer. Strong, diffuse staining for
c-kit
was seen in a proportion of synovial sarcomas, osteosarcomas, and Ewing sarcomas. Strong, diffuse staining was less common in neuroblastomas, Wilms' tumors, and rhabdomyosarcomas and was negative in alveolar soft part sarcomas and desmoplastic small round cell tumors. Tumors with strong, diffuse staining for
c-kit
in a pattern similar to gastrointestinal stromal tumor may represent suitable targets for new therapeutic agents.
...
PMID:C-kit expression in pediatric solid tumors: a comparative immunohistochemical study. 1191 27
A novel subtype of myeloid leukemia exhibiting a partial differentiation of mast cell-lineage cells is described. The disease is characterized by an increase in myeloblasts as well as an increase in immature (blast-like) metachromatic cells (>10% in bone marrow or blood smears). Metachromatic cells express
KIT
(CD117) and tryptase, but lack basophil-related antigens. In contrast to mast cell leukemia/systemic mastocytosis, metachromatic cells do not express CD2 or CD25, do not form multifocal dense aggregates in the bone marrow, and do not exhibit transforming mutations at codon 816 of
c-kit
. In the few patients recorded so far, a complex karyotype without recurring anomaly was found. The prognosis appears to be grave, although complete remission in response to chemotherapy has been described.
...
PMID:Myelomastocytic leukemia: myeloid neoplasm characterized by partial differentiation of mast cell-lineage cells. 1203 70
Mast cells (MCs) are multifunctional hematopoietic effector cells that produce and release an array of biologically active mediator substances. Growth and functions of MCs are regulated by cytokines, other extracellular factors, surface and cytoplasmic receptors, oncogene products, and a complex network of signal transduction cascades. Key regulators of differentiation of MCs appear to be stem cell factor (SCF) and its tyrosine kinase receptor
KIT
(
c-kit
proto-oncogene product=CD117), downstream-acting elements, and the mi transcription factor (MITF). Signaling through
KIT
is negatively regulated by the signal regulatory protein (SIRP)-alpha (CD172a)-SHP-1-pathway that is disrupted in neoplastic MCs in MC proliferative disorders. Both
KIT
and FcepsilonRI are involved in MC activation and mediator release. Activation of MCs through FcepsilonRI is associated with increased expression of activation-linked membrane antigens as well as with signaling events involving Lyn and Syk kinases, the phosphatidylinositol-3-kinase-pathway, Ras pathway, and the phospholipase C-protein kinase C pathway. A similar network of signaling is found in SCF-activated MCs. The current article gives an overview on signal transduction-associated and activation-linked antigens expressed in human MCs. Wherever possible the functional implication of signaling pathways and antigen expression are discussed.
...
PMID:Signal transduction-associated and cell activation-linked antigens expressed in human mast cells. 1204 64
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