Quantitative evaluation of immunohistochemical staining in gastrointestinal stromal tumors.
OBJECTIVE
To evaluate the differences among pathologists' interpretations in gastrointestinal stromal tumors (GISTs) and to demonstrate the usefulness of quantitative pathology in the assessment of immunohistochemical staining.


METHODS
Twenty GISTs were separately evaluated by 4 pathologists by the visual estimation method using a 6-antibody panel. Each case was then quantitatively measured with a computer-assisted image analysis system by 2 pathologists. Cohen's kappa test was performed for statistical analysis.


RESULTS
All GISTs showed some degree of expression of CD 117, CD34, SMA and Ki-67. No case was immunoreactive for desmin or S-100 protein. There were remarkable differences in the pathologists' visual estimations. Moreover, the discrepancies between visual and quantitative methods were noteworthy. The differences in interpretations showed the greatest variability for Ki-67, which is known to be related to poor prognosis.


CONCLUSIONS
Quantitative pathology in assessment of immunohistochemical staining of GISTs may improve the consistency in the interpretation of staining results and provide some degree of reproducibility.
Ozcan
Ayhan
A
Department of Pathology, School of Medicine, Gulhane Military Medical Academy, 06018 Etlik, Ankara, Turkey. aozcan06018@yahoo.com
Karslioglu
Yildirim
Y
Kurt
Bulent
B
Onguru
Onder
O
Gunhan
Omer
O
D000328:Adult; D000368:Aged; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry / Q000592:standards*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation