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.
|Diagnosis (n)||Intensity (n)||Distribution (n)||Negative (n)|
|Squamous cell carcinoma (12)||7||0||0||0||7||5|
|Sarcomatoid carcinoma (1)||0||0||0||0||0||1|