Aims: The histopathological diagnosis of gastrointestinal stromal tumours (GIST) is typically made based on a combination of clinical and morphological features supported by immunohistochemistry studies. The aim of this study was to examine the staining quality, sensitivity, specificity and utility of antibodies used commonly in GIST diagnosis. Methods and results: Immunohistochemistry with a panel of antibodies [CD117, DOG1, protein kinase C (PKC)-theta, nestin, CD34, smooth muscle actin (SMA), desmin, S100 and CD171] was performed on whole sections from 187 GIST and 29 gastrointestinal mesenchymal tumours, and on several microarrays including 355 GISTs and 120 soft tissue sarcomas. Results showed that DOG1 and CD117 were the most sensitive and specific antibodies used in GIST diagnosis. PKC-theta and nestin were sensitive, but less specific, also staining other spindle cell tumours commonly considered in the differential diagnosis of GIST. CD34 staining was less sensitive than many of the other antibodies and of limited aid in diagnosis. The smooth muscle markers SMA and desmin, together with the neural marker S100, were unhelpful in confirming a diagnosis of GIST, but were particularly useful in the exclusiondiagnosis of other gastrointestinal mesenchymal tumour types. Conclusions: In the majority of histologically suspected GISTs a combination of CD117 and DOG1 immunostaining is sufficient to confirm the histological diagnosis.

CD117, CD34 antibody, CD34 antigen, DOG1, DOG1 antibody, DOG1 protein, GIST, article, controlled study, desmin, differential diagnosis, exon, fibromatosis, gastrointestinal stromal tumor, gene expression, gene mutation, granular cell tumor, histopathology, human, human tissue, immunodiagnosis, immunohistochemistry, leiomyoma, leiomyosarcoma, membrane protein, monoclonal antibody, nestin, neurilemoma, outcome assessment, polymerase chain reaction, priority journal, protein S 100, protein kinase C theta, sensitivity and specificity, smooth muscle actin, soft tissue sarcoma, solitary fibrous tumor, spindle cell carcinoma, stem cell factor receptor, stem cell factor receptor antibody, tissue microarray, unclassified drug,
Erasmus MC: University Medical Center Rotterdam

Novelli, M, Rossi, S, Rodriguez-Justo, M, Taniere, P, Seddon, B, Toffolatti, L, … Hogendoorn, P.C.W. (2010). DOG1 and CD117 are the antibodies of choice in the diagnosis of gastrointestinal stromal tumours. Histopathology, 57(2), 259–270. doi:10.1111/j.1365-2559.2010.03624.x