title: Light microscopic demonstration of the microlumen of ependymoma: a study of the usefulness of antigen retrieval for epithelial membrane antigen (EMA) immunostaining.
abstract: To determine the origin of dotlike epithelial membrane antigen (EMA) immunoreactivity of ependymoma, which is consistent with the eosinophilic globular body in hematoxylin and eosin (H&E) stain, an immunoelectron microscopic study was undertaken. The usefulness of antigen retrieval pretreatment in detecting the dotlike EMA immunoreactivity in ependymomas was also studied. The materials were 29 ependymomas, 7 autopsy brains as a normal control, and 50 brain tumors of various types. The study confirmed that most of the brown dots in EMA immunostain in ependymoma represented microlumina of tumor cells. In ependymomas, plain EMA immunostaining showed dotlike positivity in only six cases (21%), and antigen retrieval pretreatment increased the number of positives up to 26 cases (90%). Antigen retrieved CD99 detected 23 positive cases (80%) in ependymomas. On the basis of the results, although some false positive findings were raised by antigen retrieval pretreatment, the authors positively recommend adoption of the technique, especially when ependymoma remains as one of the differential diagnoses of the tumor.
authors.affiliation: Isobe Clinic, Sagamihara, Kanagawa 228-0827, Japan. nkawano@jcom.home.ne.jp
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kawano
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Yasui
authors.forename: Satoshi
authors.initials: S
authors.lastname: Utsuki
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Oka
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Fujii
authors.forename: Shohei
authors.initials: S
authors.lastname: Yamashina
mesh_terms: D000071443:12E7 Antigen; D015703:Antigens, CD / Q000096:biosynthesis; D001932:Brain Neoplasms / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000096:biosynthesis; D004806:Ependymoma / Q000378:metabolism*; D005189:False Positive Reactions; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D018396:Mucin-1 / Q000096:biosynthesis*; D013194:Staining and Labeling / Q000379:methods
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D018396:Mucin-1