KIT Gene Immunohistochemistry (IHC)
Description
KIT Gene Immunohistochemistry (IHC) is the expression of the KIT gene in tumor tissue specimens based on immunohistochemical (IHC) stains. A positive test is a diagnostic and predictive marker for GIST tumors. KIT is a gene that regulates cell growth and differentiation. Mutations of this gene become oncogenes and cause a gastrointestinal stromal tumor to ignore cellular control signals. About 85-90% of GIST tumors contain oncogenic mutations of the KIT receptor gene. KIT immunohistochemistry is a special immunofluorescent stain that turns mutated cells brown and confirms a diagnosis of GIST. The presence of the KIT gene also indicates that the patient may respond to Gleevec or Sutent.Notes
**Note 1:** **Physician Statement** * Physician statement of KIT IHC can be used to code this data item when no other information is available. **Note 2:** **Results from nodal or metastatic tissue** * May be used for KIT Gene immunohistochemistry| Code | Description |
|---|---|
| 0 | KIT negative/normal; within normal limits |
| 1 | KIT positive |
| 7 | Test ordered, results not in chart |
| 8 | Not applicable: Information not collected for this case (If this information is required by your standard setter, use of code 8 may result in an edit error.) |
| 9 | Not documented in medical record Cannot be determined by pathologist KIT not assessed or unknown if assessed |