title: Oncofetal protein IMP3, a new diagnostic biomarker to distinguish malignant mesothelioma from reactive mesothelial proliferation.
abstract: The distinction of malignant mesothelioma from reactive mesothelial proliferation remains to be a major challenge for surgical pathologists. In this study, we investigated whether insulin-like growth factor II messenger ribonucleic acid-binding protein 3 (IMP3), an oncofetal protein, can be used as a biomarker to distinguish between malignant and reactive mesothelial cells. A total of 109 cases (mesothelioma, n=45; reactive mesothelial proliferation, n=64) were examined by immunohistochemistry for IMP3 expression. IMP3 showed strong cytoplasmic staining in 33 of 45 (73%) mesothelioma cases. In contrast, the expression of IMP3 was undetectable in all (64 cases) benign reactive mesothelial proliferations. Among the IMP3-positive mesotheliomas, 27 (82%) exhibited diffuse IMP3 expression. The vast majority of IMP3-positive subtypes of mesotheliomas showed IMP3 expression in >50% of malignant cells, as this diffuse staining pattern occurred in 17 (81%) cases of epithelial, 4 (100%) cases of sarcomatoid, and 6 (75%) cases of mixed types of mesothelioma. In addition, 2 cases, which were initially diagnosed as atypical mesothelial proliferations and later confirmed to be mesotheliomas, showed diffuse IMP3 expression. Our findings suggest that IMP3 is a new positive biomarker for malignant mesothelioma. IMP3 immunohistochemical staining can be used as an adjunct tool in the distinction of malignant mesothelioma from reactive mesothelial proliferations.
authors.affiliation: Department of Pathology, University of Massachusetts Medical Center, One Innovation Drive, Worcester, MA 01605, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Shi
authors.forename: Armando E
authors.initials: AE
authors.lastname: Fraire
authors.forename: Peiguo
authors.initials: P
authors.lastname: Chu
authors.forename: Kristine
authors.initials: K
authors.lastname: Cornejo
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Woda
authors.forename: Karen
authors.initials: K
authors.lastname: Dresser
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Rock
authors.forename: Zhong
authors.initials: Z
authors.lastname: Jiang
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D049109:Cell Proliferation; D003937:Diagnosis, Differential; D004848:Epithelium / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia; D008654:Mesothelioma / Q000175:diagnosis* / Q000378:metabolism; D010534:Peritoneal Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D010537:Peritoneum / Q000378:metabolism / Q000473:pathology; D010994:Pleura / Q000378:metabolism / Q000473:pathology; D010997:Pleural Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C498780:IGF2BP3 protein, human; D016601:RNA-Binding Proteins