Collaborative Stage

Note 1: Most GIST tumors have oncogenic mutations of the KIT gene, which is located on chromosome 4q. This test detects expression of the KIT gene in tumor tissue sections using immunohistochemical stains. Test results will be available in the pathology report. A positive test helps to establish the diagnosis of GIST and to identify patients for whom treatment with agents such as imatinib (Gleevec) is appropriate.
Note 2: Another name for KIT is CD117.
Note 3: See Site-Specific Factor 13 for coding information about specific mutations of the KIT gene detectable with molecular testing. See Site-Specific Factor 14 for coding information about mutations of the PDGFRA gene.

Code	Description
010	Positive
020	Negative/normal; within normal limits
030	Borderline; undetermined whether positive or negative
988	Not applicable: Information not collected for this case
997	Test ordered, results not in chart
998	Test not done (test was not ordered and was not performed)
999	Unknown or no information Not documented in patient record

CS Site-Specific Factor 12
KIT Gene Immunohistochemistry (IHC)