The Utility of GLUT-1, CD146 and KOC Immunostains in Distinguishing Malignant Mesothelioma and Reactive Mesothelial Cells from Pleural Effusion
Hongbing Deng, Jianhiu Shi, Fan Lin. Geisinger Medical Center, Danville, PA; Geisinger Wyoming Valley, Wilkes-Barre, PA
Background: Pleural effusion is an effective way to detect malignant mesothelioma (MM). However, it is always a cytologically diagnostic challenge to differentiate malignant mesothelial cells from reactive mesothelial cells (RMC). Several recent studies have indicated that GLUT-1, CD146 and KOC (IMP3) are useful immuno-markers for distinguishing MM from RMC. However, these markers were studied separately. Only one comparative analysis was reported and done in surgical specimen. The aim of this study is to evaluate the cytologic utility of GLUT, CD146 and KOC as a diagnostic panel of markers in differentiating MM from RMC in pleural fluid specimen.
Design: We performed a retrospective search for MM diagnosed from pleural effusion specimen in our institution. A total 24 MM cases were found over past 7 years. Because of legal issue, only 8 cases were available for this study. 24 cases of benign pleural effusion with reactive mesothelial cells were selected. All diagnoses were confirmed by tissue biopsy and also support by clinical history and radiology. Immunohistochemical staining for GLUTA-1(355A-16, Cellmarque), CD146 (AC-0052, Epitomics) and KOC (M3625, DAKO) were performed on cell block sections. The stain was recorded as positive when more than 5% of tumor or mesothelial cells were stained.
Results: Of 8 MM cases, 7 were positive for GLUT-1; 6 positive for CD146 and 5 positive for KOC. The 1 GLUT-1 negative MM case is positive for CD146. All RMC cases are negative for CD146 and KOC. Only 1 of 24 RMC case showed focal weakly GLUT-1 stain. As a diagnostic panel for MM, GLUT-1, CD146 and KOC showed sensitivity 87.5%, 75% and 62.5%, respectively, and specificity 95.8%, 100% and 100%. The staining results are summarized in Table 1.