Definite Classification of Specific Gene Gastrointestinal Stromal Tumor (GIST) using the Immunohistochemical Technique 20 Cases in Rajavithi Hospital from January 2016 to December 2016
Tujinda S, MS1, Kuakpaetoon T, MD1
Affiliation : 1 Department of Pathology, Rajavithi Hospital, College of Medicine, Rangsit University, Bangkok, Thailand
Background : A Gastrointestinal Stromal Tumor (GIST) is a mesenchymal tumor of the gastrointestinal tract. It originates in the
Interstitial Cells of Cajal (ICC), the pacemaker cells that produce mechanical muscle contractions. It can occur anywhere in the
entire gastrointestinal (GI) tract, but it is most commonly found in the stomach, followed by the small bowel and colon, and there
may also be extragastrointestinal involvement. Pathogenic mechanisms of GIST include Kit or PDGFRA proto-oncogene mutation
which autostimulate Kit Tyrosine Kinase function. Mutational status can act as a prognostic factor for predicting specific response
to treatment with tyrosine kinase inhibitors; consequently, GIST is classified into three groups: Kit Mutation; PDGFRA Mutation;
and Wild-Type. The diagnosis of GIST relies heavily on the demonstration of specific tumor marker expressions (CD 117, CD34 and
DOG1) using the Immunohistochemical Technique (IHC).
Objective : To classify GIST using the Immunohistochemical Technique (IHC)
Materials and Methods: Twenty paraffin-embedded tissue blocks of GIST were cut for immunostaining. The specific primary
antibodies were CD117, CD34 and DOG1. The immunoreactivity was evaluated for classification of GIST.
Results : Eleven cases (55.0%) were diagnosed as Kit Mutation, two (10.0%) were PDGFRA Mutation, and seven cases (35.0%) were
wild-type.
Conclusion : GIST is the most common mesenchymal tumor of the digestive tract. Definite classification of specific gene mutation
with the IHC technique is a major step towards guidance for targeted therapy and prognosis.
Keywords : Gastrointestinal stromal tumor (GIST), Immunohistochemical technique (IHC), CD117, CD34, DOG1, Kit mutation, PDGFRA mutation, Wild-type mutation.
