DOG1: Utility in Diagnosing Gastrointestinal Stromal Tumors on Fine Needle Aspiration.
Richard Kraus, Cynthia Cohen, Momin T Siddiqui. Emory University Hospital, Atlanta, GA
Background: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the GI tract, and the majority contain KIT or PDGFRA activating mutations. Fine needle aspiration biopsy (FNAB) is a valuable tool in the diagnosis of GIST, and may allow for pre-operative therapy with tyrosine kinase inhibitors (TKI). Because of the morphologic diversity of these tumors, routine diagnosis of GIST often relies on C-Kit immunohistochemical staining in addition to morphologic findings. However, up to 15% of GISTs are C-Kit negative. Antibodies with increased sensitivity and specificity for detection of C-Kit negative GIST cases could be of value, especially since some of these cases may also benefit from TKI therapy.
Design: Immunohistochemical staining for DOG-1, C-kit (CD117), and protein kinase C theta (PKCθ) was performed on FNA cell block preparations representing 18 GISTs, 17 leiomyosarcomas, 16 melanomas, 16 schwannomas and 11 adenoid cystic carcinomas (ACC).
|DOG-1||18/18 (100%)||0/17 (0%)||0/16 (0%)||0/16 (0%)||0/11 (0%)|
|C-Kit||13/18 (72.2%)||1/17 (5.9%)||4/16 (25%)||0/16 (0%)||10/11 (90.9%)|
|PKCθ||6/18 (33.3%)||1/17 (5.9%)||5/16 (31.6%)||0/15 (0%)||1/10 (10%)|