• All IHC stains will include a positive control tissue

• The primary use for this antibody is in the diagnosis of GISTs. Although C-Kit is a more sensitive marker than CD34 in the staining of GISTs, it is recommended that both markers be used
• Clinically malignant GISTs have shown loss of either C-Kit or CD34 or both; loss of either marker is not an absolute indicator of malignancy, however, as in one series, some benign tumors showed loss of CD34 but not C-Kit
• C-Kit expression has been detected quite consistently in small cell carcinoma of the lung and in seminoma/dysgerminoma
• Other tumors in which C-Kit expression has been reported (although relatively rarely) include large cell, squamous cell and adenocarcinomas of the lung, glioblastomas, breast carcinoma, pheochromocytoma and immature teratoma
• C-Kit has also been detected in various normal tissues, including glial cells, cells of the adrenal medulla, mast cells and melanocytes in the skin, and ductal epithelial cells of the breast
• GIST tumors that are C-Kit positive have recently been found to be responsive to Gleevec therapy

Submit a formalin-fixed, paraffin embedded tissue block

Formalin-fixed, paraffin embedded (FFPE) tissue block

FFPE tissue section mounted on a charged, unstained slide

Ambient (preferred)

• Unlabeled/mislabeled block
• Insufficient tissue
• Slides broken beyond repair

Immunohistochemical staining and microscopic examination

If requested, an interpretive report will be provided

Specifications

• Reacts with C-Kit (CD117), a tyrosine-kinase receptor
• Stains the interstitial cells of Cajal (ICCs), cells implicated in the regulation of gut peristalsis; these cells appear to be the cell of origin in the majority of gastrointestinal stromal tumors (GISTs)
• ICCs appear to be the only cells in the gut that are positive for C-Kit, CD34 and vimentin
• C-Kit will also stain bone marrow stem cells, mast cells, melanocytes, and germ cells

Staining pattern

• Cytoplasmic granular staining

References

1. Sircar K et al: Interstitial Cells of Cajal as Precursors of Gastrointestinal Stromal Tumors. Am J SurgPathol 23(4):377-89, 1999.
2. Matsuda R et al: Expression of the C-Kit Protein in Human Solid Tumors and in Corresponding Fetal and Adult Normal Tissues. Am J Pathol 142: 339-46, 1993.
3. Tsuura Y et al: Preferential Localization of C-Kit Product in Tissue Mast Cells, Basal Cells of Skin, Epithelial Cells of Breast, Small Cell Lung Carcinoma and Seminoma/Dysgerminoma in Human Tissue: Immunohistochemical study on Formalin-fixed, Paraffin-embedded Tissues. Virchows Archiv 424:135-41, 1994.
4. Joensuu, H er al: Effect of tyrosine inhibitor ST1571 in a patient with a metastatic GIST. New England Journal of Medicine 2001, 344:1052-1056.