The Lack of CD34 Expression in Gastrointestinal Stromal Tumors is Related to Cystic Degeneration Following Imatinib Use

Abstract

Objective: We evaluated the characteristics of the gastrointestinal stromal tumors that showed discrepancies between their assessment using the Response Evaluation Criteria in Solid Tumor (RECIST) and Choi's criteria. We also investigated the clinical applicability of Choi's criteria to Korean gastrointestinal stromal tumor patients undergoing imatinib therapy. Methods: Patients with advanced gastrointestinal stromal tumors treated with frontline imatinib were analyzed. Computed tomography images of these patients were reviewed and genotyping for the KIT and PDGFRA genes was performed. Immunohistochemical staining of c-KIT, CD34, platelet derived growth factor receptor-alpha, platelet derived growth factor receptor-beta, AKT, P-ERK and vascular endothelial growth factor was followed. Results: Ninety-five patients were enrolled. When using Choi's criteria to evaluate the 61 patients who achieved at least partial response by Choi's criteria, 27 patients showed discrepancies in their response to treatment between these two sets of criteria. A lack of CD34 expression in tumors was found to be related to cystic degeneration after imatinib treatment (P ¼ 0.001). Patients who showed partial response by Choi's criteria but stable disease by RECIST criteria had a similar progression-free survival to cases who showed a partial response under both systems (P ¼ 0.951). Conclusions: Gastrointestinal stromal tumors showing cystic degeneration after imatinib treatment lack CD34 expression. Choi's criteria have a clinical value in terms of the progressionfree survival in Korean patients treated with imatinib.

Does Immunohistochemistry Provide Additional Prognostic Data in Gastrointestinal Stromal Tumors?

“…Conversely with the results of Bertucci's analysis, CD34 (+) patients had significantly shorter progression-free intervals for imatinib. This finding was compatible with the result of another study which showed that the tumors which present with a cystic degeneration after imatinib therapy were mostly CD34 (-) tumors (Koh et al, 2012). Therefore, CD34 immunoreactivity seems to be both negative predictive and prognostic factor.…”

Imaging therapy response of gastrointestinal stromal tumors (GIST) with FDG PET, CT and MRI: a systematic review

“…Koh et al reported on discrepancies between RECIST- and Choi-based response in 27/61 patients, who responded to imatinib with cystic degeneration related to lack of CD34 expression after treatment. Choi criteria correlated significantly stronger with progression-free survival (PFS) than RECIST [ 14 ].…”

The changing face of GIST: implications for pathologists

“…40,41 In this context, loss of KIT expression may be a predictor of disease recurrence. Various morphological changes (such as hypocellularity, hyalinised or myxoid stroma, and necrosis, or a change from spindled to epithelioid or pleomorphic cytomorphology) have been described, and KIT expression may be completely lost, as may CD34.…”