C-Kit receptor

A transmembrane receptor with tyrosine kinases activity expressed in many normal tissues.

KIT is a type III transmembrane tyrosine kinase.

When stem cell factor binds its ligand the receptor mediates hematopoiesis, gametogenesis and melanogenesis.

Binding of its ligand, stem cell factor results in receptor dimerization, autophosphorylation, and activation a number of signaling pathways: allowing control over cell growth, proliferation, invasion, apop- ptosis inhibition and metastases of malignant cells.

Single mutations result in cancer cell survival as in gastrointestinal stromal tumors.

Activation in the stem cell factor (SCF) ‘C-Kit pathway mutations enhance tumor growth and decrease apoptosis in many malignancies.

A protein also known as CD117 helps differentiate gastrointestinal stromal tumors from other gastrointestinal mesenchymal tumors which do not express CD117, such as leiomyoma.

The coding gene C-kit is the normal cellular homologue of a viral oncogene.

KIT Mutation in GIST does not cause KIT expression, but it modifies KIT function.
KIT and PDGFR activation by their ligands  regulates cell functions including: proliferation, apoptosis, chemotaxis, and adhesion.
KIT functions are critical for development and maintenance of different cell types including:  hematopoietic  cells, mast cells, melanocytes and gametocytes.

Interstitial cells of Cajal are KIT positive and GIST may be a neoplasm from these cells.

KIT mutations is expressed in some melanomas, and loss of its expression is seen with progression of disease from superficial to invasive disease, suggesting that KIT possesses tumor suppressor functions.

In patients with advanced melanoma KIT gene mutations, treatment with imatinib results in clinical responses in a subset of patients (Carvajal RD et al).

KIT normally expressed on melanocytes and plays a critical role in melanocyte migration, survival, proliferation and differentiation.

KIT mutations and mutations have been identified in melanomas arising from the mucosal, acral or chronically sun damage surfaces.

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