title: P-glycoprotein expression in osteosarcoma: a basis for risk-adapted adjuvant chemotherapy.
abstract: Previous reports on osteosarcomas treated with multi-agent chemotherapy have shown that P-glycoprotein expression is a reliable prognostic indicator. The current thinking is that, of the several agents used for the treatment of osteosarcoma, only doxorubicin is involved in drug resistance mediated by P-glycoprotein. This study examines the relationship of P-glycoprotein expression to clinical outcome in osteosarcomas, treated only with doxorubicin in addition to surgery, to determine if the prognostic significance of P-glycoprotein expression reflects the ability of osteosarcoma to respond to this drug. The expression of P-glycoprotein in tumor specimens was assessed by immunohistochemistry in 37 nonmetastatic, operable osteosarcomas treated at a single institution with doxorubicin as a single adjuvant drug. The P-glycoprotein status was analysed in relation to the length of event-free survival. A widespread pattern of P-glycoprotein expression in tumor cells at diagnosis was significantly associated with a higher rate of systemic relapse (p < 0.001). On comparison of this group of patients with a similar series of 92 patients, all treated with multi-agent chemotherapy plus surgery of the primary lesion and previously analysed for P-glycoprotein status, only P-glycoprotein-positive, doxorubicin-resistant tumors consistently benefited from the addition of drugs other than doxorubicin (p < 0.001). Osteosarcomas with different abilities to respond to adjuvant chemotherapy can be identified by the expression of P-glycoprotein in tumor cells at the clinical onset. P-glycoprotein status may serve as a basis for risk-adapted, individualized therapeutic regimens. Standard programs are sufficient for P-glycoprotein-negative osteosarcomas, whereas P-glycoprotein-positive tumors may benefit from the use of more intensive therapeutic approaches.
authors.affiliation: Department of Musculoskeletal Oncology, Istituti Ortopedici Rizzoli, University of Bologna, Italy. nicola.baldini@ior.it
authors.forename: N
authors.initials: N
authors.lastname: Baldini
authors.forename: K
authors.initials: K
authors.lastname: Scotlandi
authors.forename: M
authors.initials: M
authors.lastname: Serra
authors.forename: P
authors.initials: P
authors.lastname: Picci
authors.forename: G
authors.initials: G
authors.lastname: Bacci
authors.forename: S
authors.initials: S
authors.lastname: Sottili
authors.forename: M
authors.initials: M
authors.lastname: Campanacci
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis*; D000293:Adolescent; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage; D014408:Biomarkers, Tumor; D001859:Bone Neoplasms / Q000737:chemistry* / Q000188:drug therapy* / Q000401:mortality; D004317:Doxorubicin / Q000008:administration & dosage*; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008297:Male; D012516:Osteosarcoma / Q000737:chemistry* / Q000188:drug therapy* / Q000401:mortality; D011379:Prognosis; D018570:Risk Assessment; D016019:Survival Analysis
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D004317:Doxorubicin