Calretinin. A selective marker of normal and neoplastic mesothelial cells in serous effusions.
OBJECTIVE
To document that a polyclonal antiserum to calretinin, a 29-kd calcium-binding protein, consistently decorates normal and tumor mesothelial cells in cytologic preparations.


METHODS
Thirty-three archival cytologic specimens from eight patients with histologically confirmed malignant mesothelioma and 13 from patients with metastatic serous effusions were destained and then immunostained with anticalretinin antiserum. For investigation of cell suspensions, four pleural fluids were incubated with anticalretinin antiserum. After cytocentrifugation the specimens were stained in accordance with the alkaline phosphatase anti-alkaline phosphatase (APAAP) method. For electron microscopic examination the cell suspensions were then incubated with gold-labeled antirabbit antibody.


RESULTS
The diagnostic sensitivity of this new immunocytochemical approach reached 100% for the eight malignant mesotheliomas investigated. Only 3 of the 13 adenocarcinomas metastatic to the serous membranes included in this study were weakly reactive, accounting for 81% specificity. Binding of anticalretinin antiserum to living mesothelial cells was consistently documented in all four cases investigated.


CONCLUSIONS
Calretinin is a very useful marker for positive identification of normal and tumor mesothelial cells in serous effusions.
Barberis
M C
MC
Emilio Bernardelli Medical Foundation, Paderno Dugnano, Milan, Italy.
Faleri
M
M
Veronese
S
S
Casadio
C
C
Viale
G
G
D000230:Adenocarcinoma / Q000473:pathology; D001202:Ascitic Fluid / Q000473:pathology*; D015415:Biomarkers; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000473:pathology; D064032:Calbindin 2; D016889:Endometrial Neoplasms / Q000473:pathology; D005260:Female; D006801:Humans; D007106:Immune Sera; D008175:Lung Neoplasms / Q000473:pathology; D008654:Mesothelioma / Q000473:pathology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D009362:Neoplasm Metastasis; D010051:Ovarian Neoplasms / Q000473:pathology; D010996:Pleural Effusion / Q000473:pathology*; D016066:Pleural Effusion, Malignant / Q000473:pathology*; D012189:Retrospective Studies; D064030:S100 Calcium Binding Protein G / Q000032:analysis*; D013274:Stomach Neoplasms / Q000473:pathology
D015415:Biomarkers; D014408:Biomarkers, Tumor; C576764:CALB2 protein, human; D064032:Calbindin 2; D007106:Immune Sera; D064030:S100 Calcium Binding Protein G