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Immunohistochemistry (IHC)
Test Description

CD117 (cKit) is a transmembrane receptor tyrosine kinase. It is expressed in many tissues and cells, such as tissue mast cells, skin basal cells, melanocytes, breast glandular epithelial cells, dermal sweat gland, esophageal glands, testicular and ovarian interstitial cells. Abnormal expression of cKit has been implicated in pathogenesis of myeloid leukemias. cKit expression has also been demonstrated in solid tumors including gastrointestinal stromal tumor (GIST), melanomas, breast carcinomas and small cell lung carcinoma. C-Kit pharmDXTM is indicated as an aid in the differential diagnosis of GIST. Accurate assessment of CD117 protein expression using cKIT testing is a critical factor in the diagnosis of GIST and is becoming increasingly important in clinical management, including the use of imatinib mesylate (Gleevec®) therapy.

Specimen Requirements
  • A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type
  • One (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns) for each test/antibody ordered
  • Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
Storage and Transportation

Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.

CPT Code(s)*
88342 x 1 or 88341 x 1
Turnaround Time

Tech-Only (stain only): 24 hours

New York Approved
Level of Service
Stain Only

*The CPT codes provided with our test descriptions are based on AMA guidelines and are for informational purposes only. Correct CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed.