GIST: Analysis of 24 cases using tissue microarray

Aims: Gastrointestinal stromal tumors (GIST) are newly in the focus of oncological interest, because its uncertain prognosis and promising new chemotherapy. This is based on immunohistochemical detection of c-kit (CD 117) antigen on tumor biopsies. Grade of differentiation, c-kit positivity were analyzed on our cases in the period 2000–2003.

Methods: A total of 24 tumors were investigated in a single tissue microarray. Immunohistochemistry with c-kit, CD34, KI67, SMA and S100 antibodies was used and differentiation was assessed by image analysis of nuclear shapes and densities.

Results: Progressive transition of reaction intensity from negative to highly positive was found in the case of c-kit antibody. This positivity was correlated with CD34 and KI67 intensity, lower level of differentiation and more frequent small intestinal localization. Conclusion: Tissue microarray is a good method for comparative analysis in GISTs. Intensity of c-kit reactions is variable. Lower differentiation of GIST correlates with c-kit positivity. C-kit negative cases were also detected.