How Useful Is GLUT-1 in Differentiating Mesothelial Hyperplasia and Fibrosing Pleuritis from Epithelioid and Sarcomatoid Mesotheliomas?
Aliya N Husain, Allen R Gibbs, Kenzo Hiroshima, Yiqing Chi, Redouane Boumendjel, Nolwenn Le Stang, Francoise Galateau-Salle. University of Chicago, IL; Llandough Hospital, Penarth, United Kingdom; Tokyo Women's Medical University Yachiyo Medical Center, Yachiyo, Japan; MESOPATH IM@EC, Caen, France
Background: Mesothelial hyperplasia (MH) and fibrosing pleuritis (FP) can be difficult to distinguish from epithelioid (MM-E) and sarcomatoid (MM-S) malignant pleural mesotheliomas. GLUT-1 is one of the isoforms of glucose transporters which is not expressed on most benign epithelia and stromal fibroblasts but is expressed in many malignancies. The few studies published show variable results regarding its sensitivity and specificity.
Design: In this retrospective study, well-characterized diagnostic cases (MH=31, FP=29, MM-E=41, MM-S=29) were collected and stained for GLUT-1 (polyclonal, DAKO). All slides were scored visually by 2 pathologists; membranous staining was scored as negative 0%, 1+ 1-10%, 2+ 11-50% and 3+ >51% cells staining.
Any membranous staining was considered positive for the overall calculation. Sensitivity was calculated as % positivity among patients with disease (MM) and specificity as % of negativity among non-diseasesd (reactive).
Results: All benign cases (n=60) were negative for GLUT-1 while 42 of 70 (60%) MM [21 of 41 (50%) MM-E and 21 of 29 (72%) MM-S] had 1+ to 3+ staining. Of the MM-E, 10 had 1+, and 11 had 2+ staining; of the MM-S 3 had 1+, 15 had 2+ and 3 had 3+ staining. The overall sensitivity was 60% and specificity was 100%. In many cases the majority of positive cells were seen adjacent to areas of necrosis.
Conclusions: Positive staining with GLUT-1 is helpful since it is positive in half of epithelioid and three-quarter of sarcomatoid MM. Although all reactive mesothelial lesions were negative, a negative stain does not exclude the diagnosis of MM. As with all IHC stains, GLUT-1 has to be used as part of a panel, and the results interpreted in the context of clinical, radiological and histological findings.
Tuesday, March 1, 2011 1:30 PM
Platform Session: Section F, Tuesday Afternoon