[1883] D2-40 as a Marker To Differentiate Malignant Mesothelioma from Non-Small Cell Carcinoma

Joema Felipe Lima, Marie Christine Aubry, Anja C Roden. Mayo Clinic, Rochester, MN

Background: The distinction of malignant mesothelioma from other malignancies is important to guide therapy. However, the morphologic differentiation of malignant mesotheliomas from other tumors can be challenging despite several proposed panels of immunostains. D2-40 is an antibody directed against human podoplanin, a transmembrane mucoprotein that is expressed in lymphatic endothelial cells. D2-40 has been proposed as a useful marker for mesothelial differentiation. However, evidence suggests that D2-40 might also be expressed in some sarcomas and sarcomatoid carcinomas. Herein we studied the expression of D2-40 in pleural malignant mesotheliomas and compared its expression pattern to lung and other metastatic non-small cell carcinomas and sarcomatoid carcinoma.
Design: 85 cases of pleural malignant mesothelioma, non-small cell carcinoma of the lung, sarcomatoid carcinoma, and metastatic adenocarcinomas were selected based on pathology reports (1995 to 2012). Sections were stained with D2-40 antibody and were reviewed by two pathologists. Staining intensity (score 0-3+) and distribution (negative, focal, diffuse) were assessed. Membranous staining with or without cytoplasmic staining was considered positive.
Results: Diagnoses, staining intensity and distribution of all cases are summarized in Table 1.

Summary of D2-40 staining intensity and distribution (n=85)
Diagnosis (n)Intensity (n)  Distribution (n) Negative (n)
 3+2+1+DiffuseFocal 
Mesothelioma      
Epithelioid (23)16201535
Biphasic (9)320504
Sarcomatoid (8)600332
Adenocarcinoma      
Lung (19)1000118
Metastatic (13)0000013
Squamous cell carcinoma (12)700075
Sarcomatoid carcinoma (1)000001


14 (of 40) malignant mesothelioma had strong (3+) and diffuse staining, 11 of which were of epithelioid type. No other malignant tumor tested revealed that staining pattern. Although some of the squamous cell carcinomas had strong (3+) staining for D2-40, staining was focal and predominantly in the periphery of the tumor cell nests.
Conclusions: Our results confirm that D2-40 is a useful marker to facilitate the distinction of malignant mesothelioma of the pleura from carcinomas. D2-40 is expressed in the majority of malignant mesotheliomas, independent of the morphologic subtype. Furthermore, strong and diffuse D2-40 expression by the tumor cells is only seen in malignant mesotheliomas. Squamous cell carcinomas can be strongly positive for D2-40 but staining is only focal. Larger studies are necessary to establish the value of D2-40 to distinguish malignant mesothelioma from sarcomatoid carcinomas and sarcomas.
Category: Pulmonary

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 283, Wednesday Afternoon

 

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