title: Effect of P-glycoprotein expression on outcome in the Ewing family of tumors.
abstract: This study was designed to determine the prognostic significance of multidrug resistance, mediated by P-glycoprotein (Pgp) expression, in Ewing sarcoma. The clinical and laboratory features, treatment protocol, and outcome of 75 patients with Ewing sarcoma or peripheral neuroectodermal tumor treated between 1972 and 1997 were reviewed. Pgp expression was tested with the monoclonal antibody JSB-1. Thirty-four (64%) of the 53 tissue samples from untreated patients stained positive for Pgp. Progression-free and overall survival were 44 and 59%, respectively, in patients with negative findings, and 28 and 41% in those with positive findings; neither difference was significant. Of the 12 relapsed patients, 6 (50%) expressed more Pgp after chemotherapy than at diagnosis and 4 (33%) expressed less. Within these subgroups, 5 out of 6 and 3 out of 4 died from the disease. No correlation was found between Pgp and known prognostic factors of Ewing tumors. Pgp expression is probably an intrinsic factor of Ewing tumors but has no correlation to prognosis.
authors.affiliation: Department of Hematology-Oncology, Schneider Children's Medical Center of Israel, 14 Kaplan Street, Petah Tiqva 49 202, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Perri
authors.forename: M
authors.initials: M
authors.lastname: Fogel
authors.forename: S
authors.initials: S
authors.lastname: Mor
authors.forename: G
authors.initials: G
authors.lastname: Horev
authors.forename: I
authors.initials: I
authors.lastname: Meller
authors.forename: D
authors.initials: D
authors.lastname: Loven
authors.forename: J
authors.initials: J
authors.lastname: Issakov
authors.forename: Y
authors.initials: Y
authors.lastname: Kollender
authors.forename: A
authors.initials: A
authors.lastname: Smirnov
authors.forename: R
authors.initials: R
authors.lastname: Zaizov
authors.forename: I J
authors.initials: IJ
authors.lastname: Cohen
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis*; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D012512:Sarcoma, Ewing / Q000737:chemistry / Q000401:mortality*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1