Hubungan antara Imunoekspresi Ki-67 dan Risiko Agresivitas Tumor pada Gastrointestinal Stromal Tumor

Abstract

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract, and arises from intestinal cells of Cajal localized in the muscular layer of the digestive tract, which functions as pacemaker cells in regulating intestinal motility. The incidence of GIST is about 3−5% of all soft tissue sarcomas. Gastrointestinal stromal tumor can occur along the gastrointestinal tract and predominantly in middle-aged and older persons, with a median age between 50 and 60 years. Histologically, there are three categories of GIST morphology such as spindle cells, epitheloid, and mixed type. A spesific marker of GIST is cluster of differentiation (CD117), which has good sensitivity and immunoreactive in 95% of GIST. The expression of Ki-67 correlates with proliferative activities and can be detected in G1, S, G2, and M phases of cell cycle but not in G0 phase. The aim of this study was to assessthe correlation between the risk of aggressive behaviors and proliferative activities as measured by Ki-67 in tumors confirmed as GIST by CD117. The method of this study was cross-sectional, performed on 29 cases of GIST from the Department of Pathology Anatomy Dr. Hasan Sadikin General Hospital/Faculty of Medicine Universitas Padjadjaran, Santo Borromeus Hospital, Immanuel Hospital, and Santosa Hospital between 2007−2012. A section from paraffin embedded tissue of 55 cases of GIST was stained with hematoxylin eosin for histological and immunohistochemical evaluations using monoclonal antibody CD117 to confirm the diagnosis of GIST. There were 29 positive cases for CD117. Further staining was performed using monoclonal antibody Ki-67. The categorized positive cells of immunoexpression of CD117 showed brown particles inside cytoplasma and the immunoexpression of Ki-67 was assessed by identification of nuclear brown staining of neoplastic cells. The result showed that there were significant correlations between the risk of tumor aggressive behaviors and immunoexpression of Ki-67 (p<0.001). In conclusion, as the immunoexpression of Ki-67 value increases, the aggressivity risk score becomes higher. Therefore, in GIST, the Ki-67 immunohistochemical analysis may help to decide which patients will have the worst prognosis. [

Keywords

• CD117
• gastrointestinal stromal tumor
• Ki-67