[P-glycoprotein expression in osteosarcoma].
One of the mechanisms by which multidrug resistance is mediated, is the mdr1 gene product, P-glycooprotein. Immunohistochemistry was performed for 63 osteosarcomas of 54 patients to investigate P-glycoprotein expression using the monoclonal antibody JSB-1. Most of the patients were children or adolescents who had received treatment under the framework of the Cooperative Osteosarcoma Study Group. In addition P-glycoprotein expression was assayed in five growth plates. Of all cases 68.5% stained positive for P-glycoprotein. Cases that had received chemotherapy showed a higher incidence (80.9%) of positive P-glycoprotein immunostaining than cases that had not received chemotherapy (66.6%). No relation could be established between P-glycoprotein expression and the response to chemotherapy, since the majority of P-glycoprotein positive biopsies showed a good response in the surgical specimen after chemotherapy. Furthermore, 42.9% of P-glycoprotein negative biopsies were classified as non-responders in the later surgical specimen. In addition to P-glycoprotein expression in osteosarcomas positive immunostaining was also detected in osteoblasts, osteocytes, osteoclasts as well as in some chondroblasts. The results indicate that P-glycoprotein expression in osteosarcomas also exists prior to chemotherapy and resembles the phenotype of normal bone tissue. However, the determination of P-glycoprotein by using immunohistochemistry in biopsies of osteosarcomas cannot predict the response to chemotherapy.
Pösl
M
M
Abteilung Osteopathologie, Pathologisches Institut, Universität, Hamburg.
Grahl
K
K
Amling
M
M
Werner
M
M
Ritzel
H
H
Stenzel
I
I
Hentz
M
M
Winkler
K
K
Delling
G
G
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D001842:Bone and Bones / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D018432:Drug Resistance, Multiple / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012516:Osteosarcoma / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1
P-Glykoproteinexpression beim Osteosarkom.