In this retrospective study, we haveinvestigated the prognostic value of angiogenesis, proliferation rate, alterationsin p53 and MDR/P-glycoprotein (Pgp) expressions in osteosarcomas from patients treatedat the Sarcoma Center,Aarhus University Hospital, Denmark from1972 through 1999, using an immunohistochemical approach. The gene discussed is ABCB1; the disease is osteosarcoma.